Vapor deposition method for preparing amorphous lithium borosilicate or doped lithium borosilicate compounds

Abstract

The present invention provides a vapor deposition method for preparing an amorphous lithium borosilicate or doped lithium borosilicate compound, the method comprising: providing a vapor source of each constituent element of the compound, wherein the vapor source comprises at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element; conveying streams of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and co-depositing the constituent elements from the vapor source on a substrate, wherein the constituent elements react on the substrate to form an amorphous compound; wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic %, based on the atomic percentage of the combination of lithium, boron, and silicon.

Description

Technical Field

[0001] The present invention relates to a method for preparing amorphous lithium borosilicate or doped lithium borosilicate compounds by chemical vapor deposition. Background Art

[0002] Due to the many applications of thin films, the deposition of materials in the form of thin films is of great significance, and a series of different deposition techniques are known. Various techniques are more or less suitable for specific materials, and the quality, composition, and properties of the produced thin films typically depend greatly on the process used for their formation. Therefore, much research has been devoted to developing deposition processes capable of producing thin films suitable for specific applications.

[0003] An important application of thin film materials is in solid state thin film unit cells or batteries such as lithium ion unit cells. Such a battery consists of at least three components. Two active electrodes (anode and cathode) are separated by an electrolyte. These components are each formed into thin films and deposited in sequence on a supporting substrate (substrate). Additional components such as current collectors, interface modifiers, and encapsulations may also be provided. In manufacturing, the components may be deposited, for example, in the order of cathode current collector, cathode, electrolyte, anode, anode current collector, and encapsulation.

[0004] In the lithium ion example, the anode and cathode are capable of reversibly storing lithium. Other requirements for the anode and cathode materials are high gravimetric and volumetric storage capacities, which can be achieved by materials of low mass and volume, while the number of lithium ions stored per unit should be as high as possible. The materials should also exhibit acceptable electronic and ionic conductivities such that ions and electrons can move through the electrodes during battery charge and discharge processes.

[0005] In addition, the anode and cathode require different properties. The cathode should exhibit reversible lithium intercalation at high potentials, while the anode should exhibit reversible lithium intercalation at low potentials.

[0006] The electrolyte physically separates the anode and cathode, so it must have extremely low electrical conductivity to prevent battery short circuit. However, in order to achieve reasonable charge and discharge properties, the ionic conductivity of the material must be as high as possible. In addition, the material must be stable during both manufacturing and cycling and not react with the cathode or anode.

[0007] A major challenge in the development of solid state batteries is to identify solid electrolytes with sufficiently high ionic conductivity, low electronic conductivity, and low mechanical stress resulting from the required electrochemical cycling and reproducible high yield production methods.

[0008] Both crystalline and non-crystalline (amorphous) materials are considered as electrolytes. Crystalline materials such as lithium lanthanum titanate (LLTO), thio-LISICON, NASICON-type (Li1+x+y Al x (Ti, Ge) 2-x Si y P 3-y O 12 )、 and Li 10 GeP2S 12 usually exhibit excellent ionic conductivity (e.g., up to 1.2 x 10 10 GeP2S 12 in the case of Li -2 S cm -1 ), and thus appear to be good candidates for electrolytes. However, these materials have problems when applied to battery systems. In the case of oxides (LLTO, thio-LISICON, and NASICON types), the transition metals within the electrolyte are prone to reduction, which results in the material exhibiting electronic conductivity and thus short-circuiting the battery. Sulfide systems such as Li 10 GeP2S 12 exhibit extremely high conductivity but are prone to decomposition when exposed to air and water, leading to the release of toxic H2S and performance degradation. In addition, both oxide and sulfide crystalline electrolytes require extremely high processing temperatures. For these reasons, crystalline electrolytes have not been used in commercial thin-film battery systems.

[0009] Amorphous electrolytes such as lithium phosphonitride oxide (LiPON), lithium silicate, and lithium borosilicate exhibit far lower levels of ionic conductivity. Although the best conductivity of these materials is approximately two orders of magnitude lower than that of crystalline materials, this has been determined to be acceptable if the electrolyte is less than 1 x 10 -6 m thick (Julien, C.M.; Nazri, G.A., Chapter 1. Design and Optimisation of Solid State Batteries. In Solid State Batteries: Materials Design and Optimization, 1994). LiPON has 3 x 10 -6 S cm -1has an acceptable ionic conductivity and has been shown to be stable relative to lithium in air and during cycling. For these reasons, plus its ease of fabrication, it has been widely adopted in first-generation solid-state batteries (Bates, J.B.; Gruzalski, G.R.; Dudney, N.J.; Luck, C.F.; Yu, X., Rechargeable Thin Film Lithium Batteries. Oak Ridge National Lab and Solid State Ionics 1993; Bates, J.B.; Dudney, N.J.; Neudecker, B.; Gruzalski, G.R.; Luck, C.F. Thin Film Battery and Method for Making Same, US 5,338,625). The amorphous nature of these electrolytes is important for their performance; crystalline LiPON has an ionic conductivity seven orders of magnitude lower than that of the amorphous material.

[0010] Thus, amorphous electrolytes are of great significance. An alternative to LiPON is amorphous lithium borosilicate. Amorphous lithium borosilicate materials with ionic conductivities comparable to LiPON have been produced, but by methods that require rapid quenching (Tatsumisago, M.; Machida, N.; Minami, T., Mixed Anion Effect in Conductivity of Rapidly Quenched Li4SiO4-Li3BO3 Glasses. Yogyo-Kyokai-Shi 1987, 95, (2), 197-201). This synthesis method produces irregular glass "fragments" that are not suitable for processing into thin-film batteries. Synthesis by sputtering of similar compositions has been attempted in thin films, but these have not been successful, producing materials with significantly reduced conductivities compared to the rapidly quenched glasses (Machida, N.; Tatsumisago, M.; Minami, T., Preparation of amorphous films in the systems Li2O2-SiO2 and Li2O-B2O 3-Si O2 by RF-sputtering and their ionic conductivity. Yogyo-Kyokai-Shi 1987, 95, (1), 135-7).

[0011] Lithium ion conducting glasses such as those from the Li2O-B2O3-SiO2 system have also been produced by the sol-gel route (Satyanarayana, N.; Muralidharan, P.; Patcheammalle, R.; Venkateswarlu, M.; and Rama Rao, GV, Investigation of sol-gel route in the synthesis of lithium ionconducting glasses. Solid State Ionics 1996, 86-88, 543-546). However, high sintering temperatures are required, which are generally considered unsuitable for thin film battery manufacturing because they can damage the underlying battery layers. In addition, it is desired that the electrolyte of the thin film battery has a low thickness, such as 15 μm or less. This is considered difficult to achieve by the sol-gel route.

[0012] To date, many different thin film deposition methods have been proposed, which have a series of disadvantages. The synthesis routes of thin films, usually referred to using the general term "physical vapor deposition", include pulsed laser deposition, flash evaporation, sputtering and thermal evaporation, the most common method being sputtering. In this method, a target of a specific composition is sputtered with a plasma formed on the target; the resulting vapor condenses on the substrate, thereby forming a thin film. Sputtering involves depositing material directly from the target. The products of sputtering vary and can include dimers, trimers or higher order particles.

[0013] An alternative is direct thermal evaporation from an element, but this is not common. Julien and Nazri (Julien, CM; Nazri, GA, Chapter 4. Materials for electrolytes: Thin Films. In Solid State Batteries: Materials Design and Optimization, 1994) suggested the synthesis of B2O3-xLi2O-yLi2O directly from elements. n X (X = I, Cl, SO4 and n = 1,2), but no results were reported, and the authors commented that "the difficulties in implementing this technique are to enhance oxygen pumping, avoid high oxygen reactivity with the heating components of the system, and make available an oxygen single atom source to enhance oxygen reactions on the surface."

[0014] Notwithstanding, the present inventors have previously demonstrated the synthesis of phosphorus-containing materials directly from the constituent elements (WO 2013 / 011326; WO 2013 / 011327). However, the complexity of the process is the use of a cracker to decompose phosphorus to enable the formation of phosphates. The synthesis of cathodes (lithium iron phosphate – Example 5, lithium manganese phosphate – Example 7) and electrolyte materials (Li3PO4 – Example 1 and nitrogen-doped Li3PO4 – Example 6) was disclosed. The deposited materials were amorphous; annealing was used to crystallize the cathode materials. While this work demonstrated two of the three basic building blocks for producing thin-film unit cells, it did not demonstrate an operable unit cell. Additionally, the ionic conductivity demonstrated in this work was too low to enable the unit cell to function properly at room temperature.

[0015] The effort required to overcome these many difficulties in various deposition processes and the complexity involved in developing new materials means that the vast majority of thin-film cells are limited to using LiPON as the electrolyte, deposited as a thin film by sputtering. Clearly, there is a desire to provide thin films of other electrolyte materials such that thin-film cell technology can be developed and improved.

[0016] In particular, there is a desire to provide an amorphous lithium borosilicate composition having improved suitability for use as an electrolyte in thin-film cells. SUMMARY OF THE INVENTION

[0017] According to a first aspect of the present invention, there is provided a vapor deposition method for preparing an amorphous lithium borosilicate or doped lithium borosilicate compound, the method comprising:

[0018] providing a vapor source of each of the constituent elements of the compound, wherein the vapor source comprises at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element;

[0019] conveying streams of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and

[0020] co-depositing the constituent elements from the vapor source onto a substrate, wherein the constituent elements react on the substrate to form an amorphous compound;

[0021] wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic percent, based on the (total) atomic percentage of the combination of lithium, boron, and silicon.

[0022] According to a second aspect of the present invention, there is provided a component comprising an amorphous lithium borosilicate or doped lithium borosilicate compound, wherein the component is obtained or obtainable by depositing the amorphous compound onto a substrate using the vapor deposition method according to the first aspect of the present invention.

[0023] According to a third aspect of the present invention, there is provided a method of manufacturing a surface-modified electrode by a vapor deposition process, the electrode comprising an electrode active material, wherein the surface of the electrode is modified by an amorphous lithium borosilicate or a doped lithium borosilicate compound, and the method comprises:

[0024] (a) providing a vapor source of the constituent elements of the amorphous compound, wherein the vapor source comprises at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element;

[0025] (b) providing an electrode;

[0026] (c) delivering a stream of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and

[0027] (d) co-depositing the constituent elements from the vapor source onto the electrode, wherein the constituent elements react on the electrode to form an amorphous compound;

[0028] wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0029] According to a fourth aspect of the present invention, there is provided a surface-modified electrode obtainable or obtained by the method according to the third aspect of the present invention.

[0030] According to a fifth aspect of the present invention, there is provided a battery comprising:

[0031] an electrolyte;

[0032] a negative electrode; and

[0033] a positive electrode;

[0034] wherein at least one of the negative electrode or the positive electrode is a surface-modified electrode, and the surface-modified electrode is according to the fourth aspect of the present invention.

[0035] According to a sixth aspect of the present invention, there is provided a method of manufacturing a battery, the method comprising depositing the electrolyte of the battery as a layer of an amorphous lithium borosilicate or doped lithium borosilicate compound using the vapor deposition method according to the first aspect of the present invention.

[0036] According to a seventh aspect of the present invention, there is provided a battery comprising:

[0037] a positive electrode;

[0038] a negative electrode; and

[0039] an electrolyte;

[0040] Wherein the electrolyte is in the form of a layer of amorphous lithium borosilicate or doped lithium borosilicate compound deposited on a substrate using the vapor deposition method according to the first aspect of the present invention.

[0041] For ease of introduction, the above and other aspects of the present invention are now discussed under appropriate section headings. However, the teachings under each section are not necessarily limited to each specific section. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0043] Figure 1 A schematic diagram showing an example device suitable for implementing the method according to an embodiment of the present invention.

[0044] Figure 2A A composition diagram of the lithium borosilicate system is shown, where the ionic conductivity of lithium borosilicate is given as a function of the composition.

[0045] Figure 2B Showing Figure 2A A more detailed view of

[0046] Figure 3 A composition diagram of the lithium borosilicate system is shown, where the crystallization temperature of lithium borosilicate is given as a function of the composition.

[0047] Figure 4 A Raman spectrum obtained for lithium borosilicate including 57.98 atomic % lithium, 27.57 atomic % boron, and 14.45 atomic % silicon is shown. DETAILED DESCRIPTION

[0048] Definition

[0049] As used herein, a range of values set forth as "X to Y" or "between X and Y" includes the end values X and Y.

[0050] As used herein, the term "battery" is considered synonymous with the term "cell" and is a device capable of generating electrical energy by a chemical reaction or facilitating a chemical reaction by introducing electrical energy.

[0051] Method

[0052] In a first aspect, the present invention provides a method for preparing amorphous lithium borosilicate (LiBSiO) or doped lithium borosilicate compounds. As used herein, the method is a vapor deposition method. The method includes:

[0053] Provide vapor sources for the respective constituent elements of a compound, wherein the vapor sources include at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element;

[0054] Transport streams of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and

[0055] Co-deposit the constituent elements from the vapor sources onto a substrate, wherein the constituent elements react on the substrate to form an amorphous compound;

[0056] Wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0057] Conventionally, it is considered that lithium borosilicate compounds or doped lithium borosilicate compounds need to contain a high level of lithium (typically more than 70 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon) to provide an acceptable level of ionic conductivity. Intuitively, one skilled in the art would expect that a decrease in the lithium level would result in a decrease in the concentration of lithium ions available for migration within the lithium borosilicate compound or doped lithium borosilicate compound. However, surprisingly, it has been found that although the lithium borosilicate compounds deposited by vapor deposition methods exhibit an overall trend of decreasing ionic conductivity with decreasing lithium content, for lithium borosilicate compounds having a lithium content in the range of 40 - 65 atomic % (based on the atomic percentages of the combination of lithium, boron, and silicon), regions of anomalously high ionic conductivity are observed.

[0058] Surprisingly, lithium borosilicate compounds having a lithium content within this range exhibit higher levels of ionic conductivity relative to certain lithium borosilicate compounds having higher lithium contents, and these ionic conductivity levels typically have an order of magnitude of 1 x 10 -7 S / cm or greater. These ionic conductivity levels are typically considered acceptable for electrolyte applications. The surprising finding that acceptable ionic conductivity levels can be provided by lithium borosilicate compounds having a relatively low lithium content has the consequence that lithium borosilicate compounds can be used as electrolytes having one or more of the following additional properties:

[0059] · Improved chemical stability (it is believed that the tendency of lithium borosilicate to form Li2CO3 upon exposure to the ambient atmosphere decreases with decreasing lithium content); and / or

[0060] · Improved thermal stability (it is believed that the crystallization temperature of lithium borosilicate increases with decreasing lithium content: crystallization of lithium borosilicate is undesirable because it is known to result in a significant decrease in ionic conductivity relative to the amorphous phase)

[0061] Thus, the method according to the first aspect of the present invention can provide the general benefits of a vapor deposition method by constituent elements (e.g., depositing a smooth, high-quality film with good compositional control) and provide a lithium borosilicate or doped lithium borosilicate compound having an acceptable level of ionic conductivity and improved chemical and / or thermal stability.

[0062] In the context of the present disclosure and with respect to all aspects of the present invention, the term "element" refers to "an element of the periodic table". The lithium borosilicate compounds formed according to the present invention thus contain constituent elements including lithium (Li) and oxygen (O). Also included are glass-forming elements, which include at least boron (B) and silicon (Si). Additionally, dopant elements may optionally be included. These may include, for example, nitrogen (N), sulfur (S), phosphorus (P), germanium (Ge), aluminum (Al), arsenic (As), titanium (Ti), aluminum (Al), zirconium (Zr), lead (Pb), gallium (Ga), tin (Sn), indium (In), bismuth (Bi), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), and antimony (Sb) or combinations thereof. Other constituent elements will depend on the specific compound being formed, but in all cases, each element in the compound is provided individually in vapor form (or, if appropriate, combined into a mixed vapor or plasma), and each vapor is deposited on a common substrate.

[0063] Also in the context of the present disclosure and with respect to all aspects of the present invention, the term "amorphous lithium borosilicate compound" refers to "an amorphous compound containing lithium, oxygen, boron, and silicon", and the term "amorphous doped lithium borosilicate compound" refers to "a compound containing lithium, oxygen, boron, silicon, and one or more other dopant elements", where "compound" is "a substance or material formed by the combination of two or more elements via a chemical reaction in a fixed or substantially fixed ratio" (understanding that in many cases, the elements are not precisely present in the compound in stoichiometric ratios). For the avoidance of doubt, the expression "amorphous lithium borosilicate or doped lithium borosilicate compound" refers to "an amorphous lithium borosilicate compound or an amorphous doped lithium borosilicate compound".

[0064] In the context of the present disclosure and with respect to all aspects of the present invention, the term "amorphous" refers to "non-crystalline solid", i.e., a solid that no longer has long-range order in its lattice. It has been found that according to the method of the present invention, if one or more of the constituent elements from which the compound is deposited are glass-forming elements, the desired compound can be deposited in amorphous form. Boron (B) and silicon (Si) are glass-forming elements included in lithium borosilicate compounds (and doped lithium borosilicate compounds). Other examples of glass-forming elements that can be included as dopant elements in the compound include germanium (Ge), aluminum (Al), arsenic (As), titanium (Ti), aluminum (Al), zirconium (Zr), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), and antimony (Sb) (Varshneya, A.K., Fundamentals of Inorganic Glasses, Academic Press, page 33).

[0065] Thus, in some embodiments, the vapor source includes at least a lithium source, at least an oxygen source, at least a boron source, and at least a silicon source. In some embodiments, the vapor source may further include a source of one or more of the following dopant elements: nitrogen, germanium, aluminum, arsenic, titanium, aluminum, zirconium, tungsten, niobium, tantalum, vanadium, and antimony. As described herein with respect to all aspects of the present invention, the boron source and the silicon source are sources of glass-forming elements.

[0066] In certain cases, the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 45 - 65 atomic percent, based on the atomic percent of the combination of lithium, boron, and silicon. In certain cases, the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 50 - 65 atomic percent, based on the atomic percent of the combination of lithium, boron, and silicon. In certain cases, the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 50 - 60 atomic percent, based on the atomic percent of the combination of lithium, boron, and silicon.

[0067] In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of 64 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of 63 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of 62 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of 61 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of 60 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0068] In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of at least 45 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of at least 46 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of at least 47 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of at least 48 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of at least 49 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a lithium content of at least 50 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0069] Typically, a lithium borosilicate compound or a doped lithium borosilicate compound has a boron content in the range of 1 - 50 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a boron content in the range of 15 - 45 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a boron content in the range of 15 - 40 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a boron content in the range of 20 - 40 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0070] In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of at least 10 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of at least 11 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of at least 12 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of at least 13 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of at least 14 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of at least 15 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0071] In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of 49 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of 48 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of 47 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of 46 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a boron content of 45 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0072] Typically, the lithium borosilicate compound or doped lithium borosilicate compound has a silicon content in the range of 1 - 30 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a silicon content in the range of 8 - 25 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, the lithium borosilicate compound or doped lithium borosilicate compound has a silicon content in the range of 10 - 25 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0073] In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of at least 5 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of at least 6 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of at least 7 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of at least 8 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0074] In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of 29 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of 28 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of 27 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of 26 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon. In some cases, a lithium borosilicate compound or a doped lithium borosilicate compound has a silicon content of 25 atomic percent or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0075] In some cases, a lithium borosilicate compound consists essentially of a system of lithium oxide in combination with silicon oxide and / or boron oxide.

[0076] In this regard, the term "consisting essentially of a system of lithium oxide in combination with silica and / or boric oxide" means that the total amount of lithium, boron, and silicon atoms in the lithium borosilicate material (expressed as a mole percentage of the total amount of atoms in the material other than oxygen) is at least 90%, preferably at least 95%, preferably at least 97%, more preferably at least 98%, even more preferably at least 99%, still more preferably at least 99.5%, even more preferably at least 99.7%, still more preferably at least 99.8%, even more preferably at least 99.9%, still more preferably at least 99.95%, even more preferably at least 99.97%, still more preferably at least 99.98%, even more preferably at least 99.99%, still more preferably at least 99.995%, even more preferably at least 99.997%, still more preferably at least 99.998%, even more preferably at least 99.999%, still more preferably at least 99.9995%, even more preferably at least 99.9997%, still more preferably at least 99.9998%, even more preferably at least 99.9999%, and most preferably 100%.

[0077] In some cases, the lithium borosilicate compound consists essentially of a system of lithium oxide in combination with silica and boric oxide.

[0078] In some cases, the lithium borosilicate compound consists essentially of a ternary system of lithium oxide in combination with silica and boric oxide.

[0079] In some cases, the composition of the lithium borosilicate compound or the doped lithium borosilicate compound lies within the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 51 atomic % Li - 32 atomic % B - 17 atomic % Si; 46 atomic % Li - 42 atomic % B - 12 atomic % Si; and 52 atomic % Li - 38 atomic % B - 10 atomic % Si; where the atomic percentages of lithium, boron, and silicon are based on the percentages of the combination of lithium, boron, and silicon.

[0080] In some cases, the composition of the lithium borosilicate compound or the doped lithium borosilicate compound lies within the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 50 atomic % Li - 39 atomic % B - 11 atomic % Si; 46 atomic % Li - 42 atomic % B - 12 atomic % Si; 51 atomic % Li - 32 atomic % B - 17 atomic % Si; and 59 atomic % Li - 18 atomic % B - 23 atomic % Si; where the atomic percentages of lithium, boron, and silicon are based on the percentages of the combination of lithium, boron, and silicon.

[0081] In certain cases, the composition of the lithium borosilicate compound or the doped lithium borosilicate compound lies in the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 53 atomic % Li - 32 atomic % B - 15 atomic % Si; and 52 atomic % Li - 38 atomic % B - 10 atomic % Si; where the atomic percentages of lithium, boron, and silicon are based on the percentages of the combination of lithium, boron, and silicon.

[0082] In certain cases, the composition of the lithium borosilicate compound or the doped lithium borosilicate compound lies in the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 56 atomic % Li - 32 atomic % B - 12 atomic % Si; and 51 atomic % Li - 32 atomic % B - 17 atomic % Si; where the atomic percentages of lithium, boron, and silicon are based on the percentages of the combination of lithium, boron, and silicon.

[0083] In certain cases, the composition of the lithium borosilicate compound or the doped lithium borosilicate compound lies in the region defined by: 60 atomic % Li - 27 atomic % B - 13 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 56 atomic % Li - 32 atomic % B - 12 atomic % Si; and 51 atomic % Li - 32 atomic % B - 17 atomic % Si; where the atomic percentages of lithium, boron, and silicon are based on the percentages of the combination of lithium, boron, and silicon.

[0084] In certain cases, the composition of the lithium borosilicate compound or the doped lithium borosilicate compound lies in the region defined by: 60 atomic % Li - 27 atomic % B - 13 atomic % Si; 60 atomic % Li - 25 atomic % B - 15 atomic % Si; 59 atomic % Li - 22 atomic % B - 19 atomic % Si; 56 atomic % Li - 32 atomic % B - 12 atomic % Si; and 53 atomic % Li - 32 atomic % B - 15 atomic % Si; where the atomic percentages of lithium, boron, and silicon are based on the percentages of the combination of lithium, boron, and silicon.

[0085] It will be understood that small amounts of other atoms may be present in the lithium borosilicate materials as described herein. In such embodiments, the compound may be described as a doped lithium borosilicate compound. Such other atoms may be present in the compound provided that the amount of such other atoms does not affect the properties of the lithium borosilicate material. Such trace amounts of other atoms may replace any of Li, B, O, and / or Si, preferably B and / or Si.

[0086] Typical examples of atoms (dopants) that can substitute for Li, B, O, and / or Si (preferably for B and / or Si) in the structure of lithium borosilicate materials include N, S, Ge, Al, P, Ti, V, Zr, Pb, Ga, As, Sn, In, Sb, Bi, Nb, Ta, and W. Preferred examples of atoms that can substitute for Li, B, O, and / or Si (preferably for B and / or Si) in the structure of lithium borosilicate materials include Al, Ti, Ge, P, V, W, S, and N. In some embodiments, the dopant element is nitrogen, and the amorphous compound is nitrogen-doped lithium borosilicate.

[0087] Typically, the dopant element is present in an amount not greater than 10 atomic % based on the percentage of the combination of lithium, boron, and silicon. In some cases, the dopant element is present in an amount not greater than 8 atomic % based on the percentage of the combination of lithium, boron, and silicon. In some cases, the dopant element is present in an amount not greater than 5 atomic % based on the percentage of the combination of lithium, boron, and silicon. It is believed that the presence of certain dopant elements can help increase the crystallization temperature of the lithium borosilicate material while maintaining an acceptable level of ionic conductivity. Therefore, it is preferred that the amount and type of dopant element do not significantly affect the proportion of those structural units (i.e., structural units selected from: orthoborate, pyrosilicate, orthosilicate, and pyrophosphate) of the lithium borosilicate compound that are believed to promote the mobility of lithium. Effectively, it is preferred that the amount and type of dopant element have no significant effect on the Raman spectrum of the lithium borosilicate compound, as discussed below with respect to the second aspect of the present invention.

[0088] To avoid doubt, when stating the amount of an element in terms of atomic percentage based on the combination of lithium, boron, and silicon or relative to the combination of lithium, boron, and silicon, this means that the amount of the element is expressed as a proportion of the total content of lithium, boron, and silicon.

[0089] In some cases, the lithium borosilicate compound and / or the doped lithium borosilicate compound do not contain phosphorus.

[0090] Typically, the lithium borosilicate compound and / or the doped lithium borosilicate compound is a glass.

[0091] It has been found that lithium borosilicate glasses as described herein exhibit high ionic conductivity while also exhibiting low electronic conductivity. It has also been found that lithium borosilicate glasses as described herein are particularly stable when in contact with lithium. These improved properties make lithium borosilicate glass compositions particularly suitable as electrode protectants, especially on the anode of a battery, including as a component of a coating on the anode.

[0092] In certain embodiments according to the first aspect of the present invention, the vapor source of oxygen can be a vapor source of atomic oxygen or molecular oxygen. In the case where the vapor source of oxygen is a vapor source of atomic oxygen, the vapor source of oxygen can include an ozone source and / or a plasma source.

[0093] Generally, the use of atomic oxygen is preferred over molecular oxygen because it is believed that the higher reactivity of atomic oxygen results in an increased deposition rate and / or greater uniformity of the deposited compound over the entire substrate.

[0094] Preferably, the vapor source of oxygen is a vapor source of atomic oxygen including a plasma source.

[0095] In the case where the vapor source of oxygen is a vapor source of atomic oxygen including a plasma source, the flow rate of oxygen can be at least about 8 x 10 -8 m 3 / s, for example at least 1 x 10 -7 m 3 / s, for example about 1.25 x 10 -7 m 3 / s to about 2 x 10 -7 m 3 / s. This is particularly preferred when the substrate temperature is below 180 °C (a deposition temperature below 180 °C allows the method of the first aspect of the present invention to be used for preparing materials in which an amorphous compound is deposited on lithium. This provides the possibility that the prepared composition can be used not only as an electrolyte in a battery but also as an electrode protector, especially on the anode of the battery (for example, an anode containing lithium as a negative electrode material). This also means that the prepared composition can be particularly suitable as an electrolyte in contact with lithium metal in a lithium-ion battery). The flow rate of oxygen corresponds to the rate at which molecular oxygen is supplied to the plasma source.

[0096] In some cases, the substrate is provided at a temperature of 160 °C or above, for example 180 °C or above. If the substrate temperature is 180 °C or above, the flow rate of oxygen is considered to be less important and can be in the range of 1 x 10 -9 m 3 / s to 1 x 10 -6 m 3 / s. Similarly, if the vapor source of oxygen is a source of molecular oxygen, the flow rate of oxygen is considered to be less important and can be in the range of 1 x 10 -9 m 3 / s to 1 x 10 -6 m 3 / s.

[0097] The upper limit of the substrate temperature is the temperature at which crystallization and a simultaneous reduction in ionic conductivity occur. It is believed that a high substrate temperature can also lead to lithium loss (however, since separate sources of the constituent elements of the amorphous compound are used, it may be possible to compensate for this through source regulation). Generally, it is preferred that the substrate temperature be 400 °C or less. In some cases, the substrate temperature can be 375 °C or less. In some cases, the substrate temperature can be 350 °C or less.

[0098] The flow rates of other vapor sources such as the lithium source, boron source, and silicon source can be the same as or different from the flow rate of oxygen. As will be understood by those skilled in the art, the flow rates of vapor sources other than oxygen can affect the composition and structure of the film. At too high a rate of other sources, the concentrations of Li, B, and Si will exceed the availability of oxygen, and in extreme cases, the film will no longer be an oxide. In some embodiments, the flow rate of lithium is from about 0.9x10 -10 m / s to about 10x10 -10 m / s, such as from about 2.5x10 -10 m / s to about 3.5x10 -10 m / s. In some embodiments, the flow rate of boron is from about 0.01x10 -10 m / s to about 1.5x10 -10 m / s, such as from about 0.1x10 -10 m / s to about 0.2x10 -10 m / s. In some embodiments, the flow rate of silicon is from about 0.01x10 -10 m / s to about 1.5x10 -10 m / s, such as from about 0.3x10 -10 m / s to about 0.4x10 -10 m / s.

[0099] In some cases, the substrate includes a surface layer supported on a bulk substrate element. The surface layer can provide a cathode for the thin-film battery, while the lithium borosilicate layer can provide an electrolyte for the thin-film battery.

[0100] Figure 1 A schematic view of an exemplary device 10 showing a method of an embodiment suitable for implementing the first aspect of the present invention. Deposition can preferably be carried out within a vacuum system 12, which can be an ultra-high vacuum system. A substrate 14 of the desired material (depending on the intended purpose of the amorphous compound to be deposited) is installed within the vacuum system 12. A heater 16 is provided to heat the substrate to the desired temperature.

[0101] Also within the system (preferably a vacuum or high-vacuum system) are a plurality of vapor sources, one for each of the constituent elements in the desired thin-film compound. The first vapor source 18 includes an oxygen source, such as an oxygen plasma source. The second vapor source 20 includes a lithium vapor source. The third vapor source 22 includes a vapor source for the glass-forming element boron. The fourth vapor source 24 includes a vapor source for the glass-forming element silicon. Depending on the number of elements included in the compound material of interest, any number of additional vapor sources (e.g., 26, 28, shown in dashed lines) may optionally be included. For example, if the compound is nitrogen-doped lithium borosilicate, one of the vapor sources may be a nitrogen source. Alternatively, in cases where oxygen is provided from a plasma source, nitrogen may be introduced through the plasma source to produce a mixed nitrogen-oxygen plasma.

[0102] The nature of each vapor source will depend on the element it delivers and the amount of control required over the delivery rate (i.e., flow rate or flux). The source may be, for example, a plasma source, particularly in the case of the oxygen vapor source. The plasma source delivers oxygen in the plasma phase, i.e., a stream (flux) of oxygen atoms, radicals, and / or ions. For example, the source may be a radio frequency (RF) plasma source. Atomic oxygen is advantageous when depositing compounds containing elements in a high oxidation state. Alternatively, an ozone source may be used to provide oxygen. If a nitrogen-doped lithium borosilicate compound is to be formed, a plasma source such as an RF plasma source may also be used to deliver the nitrogen component vapor.

[0103] Electron beam evaporators and Knudsen cells (K-Cells) are other examples of vapor sources; these are well-suited for materials with low vapor pressures. In both cases, the material is held in a crucible and heated to produce a flow of the material. The Knudsen cell uses a series of heating wires around the crucible, while in an electron beam evaporator, heating is achieved by using magnets to direct a high-energy electron beam onto the material.

[0104] Other example vapor sources are effusion cells and cracking sources. However, embodiments of the present invention eliminate any need for cracking and thus avoid the complexities inherent in using such sources. Additional alternative vapor sources will be apparent to those skilled in the art.

[0105] During the deposition process, controlled flow rates or fluxes of each of the constituent elements are released from their respective vapor sources 18 - 28 onto the heated substrate 14, and the various elements are then co-deposited.

[0106] The elements then react on the substrate 14 to form an amorphous thin-film layer 29 of lithium borosilicate or doped lithium borosilicate compound.

[0107] In some embodiments, co-depositing the constituent elements onto a substrate includes co-depositing the constituent elements directly onto the surface of the substrate. In some embodiments, co-depositing the constituent elements onto a substrate includes co-depositing the constituent elements onto one or more layers supported on the substrate.

[0108] In some embodiments, the substrate is coated (covered, enveloped) with a layer of the amorphous compound as described herein. In some embodiments, the amorphous compound completely coats the surface of the substrate. In some embodiments, the amorphous compound partially covers the surface of the substrate.

[0109] In some embodiments, the substrate is lithium or comprises lithium. In some embodiments, the substrate comprises lithium. In some embodiments, the substrate consists essentially of lithium. In some embodiments, the substrate consists of lithium.

[0110] The reaction of the constituent elements to form a compound preferably occurs on the surface of the substrate rather than in the gas phase before deposition onto the substrate. Although not wishing to be bound by theory, it is believed that the constituent elements in vapor form collide with the surface of the substrate and adhere to the surface of the substrate, where the atoms of each element then move on the surface and are thus able to react with each other to form the amorphous compound.

[0111] The process is preferably carried out in a high vacuum. As understood by those skilled in the art, the term "high vacuum" refers to a pressure of 1 x 10 -7 torr to 1 x 10 -2 torr (1.33 x 10 -5 Pa to 1.33 Pa). In some embodiments, the total pressure in the chamber is less than about 1 x 10 -1 Pa, such as less than about 5 x 10 -2 Pa, such as less than about 1 x 10 -2 Pa, such as less than about 5 x 10 -3 Pa, such as less than about 1 x 10 -3 Pa. Carrying out the process in a partial vacuum ensures that the mean free path (the average distance traveled before colliding with another particle) of the gas-phase particles traveling in the vacuum from their respective sources is long, such that the probability of collisions between the particles before deposition onto the substrate is minimized. Thus, advantageously, the distance from the source to the substrate can be set to be less than the mean free path to increase the probability that the particles reach the substrate without colliding, thereby avoiding gas-phase interactions. The reaction of the constituent elements can thus be restricted to the substrate surface and the quality of the thin-film compound material is improved.

[0112] According to a first aspect, a significant advantage of the present invention is that the composition of the element-deposited compound allows direct control of the compound composition via the deposition rates of the constituent elements. The flow rate or flux of each element can be independently controlled by appropriate operation of its respective vapor source, such that the chemical composition of the deposited compound can be adjusted according to strict requirements, if desired. Thus, by controlling the flux of each constituent element and thus the deposition rate affected thereby, the stoichiometry of the deposited compound can be directly controlled. Conventional deposition techniques such as sputtering and pulsed laser deposition can suffer from preferential loss of lighter elements and are thus more difficult to control the proportion of elements in the final compound.

[0113] Moreover, deposition directly from the constituent elements eliminates the need for sputtering targets or precursors and allows additional elements to be introduced directly without the need to prepare new deposition targets. Further, it enables the deposition of smooth and dense films with undamaged surfaces. Vapor sources such as the vapor sources exemplified above produce lower energy particles compared to the particles generated by sputtering; this lower energy prevents the formation of clusters and reduces the surface roughness of the deposited thin film, which is also a problem with pulsed laser deposition.

[0114] Importantly, according to the first aspect, the present invention allows the formation of amorphous lithium-containing compounds. The amorphous nature makes the compounds suitable for use as electrolytes in thin film batteries. Under conventional synthesis conditions for both bulk and thin film samples, it is known that these compounds crystallize, which impairs their performance as electrolytes. Thus, the present invention is beneficial in providing a technique for preparing lithium-based thin film electrolytes.

[0115] Component

[0116] In a second aspect, the present invention may provide a composition comprising an amorphous lithium borosilicate or doped lithium borosilicate compound, wherein the composition is obtained or obtainable by depositing an amorphous compound on a substrate using a vapor deposition method, the method comprising:

[0117] providing vapor sources for the respective constituent elements of the compound, wherein the vapor sources include at least a lithium source, an oxygen source, a boron source, a silicon source, and optionally a source of at least one dopant element;

[0118] transporting streams of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and

[0119] co-depositing the constituent elements from the vapor sources on a substrate, wherein the constituent elements react on the substrate to form an amorphous compound;

[0120] wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic %, based on the atomic percentage of the combination of lithium, boron, and silicon.

[0121] The gas-phase deposition method may include one or more features of the method according to the first aspect of the present invention.

[0122] In some embodiments, the amorphous compound has at least about 1×10 -7 S / cm, such as at least about 5×10 -7 S / cm, such as at least about 1×10 -6 S / cm, such as at least about 1×10 -6 S / cm, such as at least about 1.1×10 -6 S / cm, such as at least about 1.2×10 - 6 S / cm, such as at least about 1.3×10 -6 S / cm of ionic conductivity at 25 °C. In certain cases, the amorphous compound has at least about 3×10 -6 S / cm of ionic conductivity at 25 °C.

[0123] Preferably, the compound has a crystallization temperature of at least 350 °C, preferably 380 °C, more preferably 400 °C.

[0124] Typically, the compound has a Raman spectrum including one or more bands selected from: 839±25 cm -1 ; 868±25 cm -1 ; 918±25 cm -1 ; and 943±25 cm -1 These bands are believed to indicate the presence of the following structural units within the lithium borosilicate or doped lithium borosilicate compound:

[0125] Table 1

[0126] Band Structural unit <![CDATA[943±25cm -1 > Orthoborate <![CDATA[918±25cm -1 > Pyrosilicate <![CDATA[868±25cm -1 > Orthsilicate <![CDATA[839±25cm -1 > Pyroborate

[0127] It is believed that the structural units listed in Table 1 facilitate the mobility of lithium within the lithium borosilicate or doped lithium borosilicate compound.

[0128] Preferably, the lithium borosilicate or doped lithium borosilicate compound contains a low proportion of those structural units that are believed not to facilitate the mobility of lithium within the compound. Examples of such structural units are listed in Table 2 together with the corresponding Raman bands.

[0129] Table 2

[0130] Band Structural unit <![CDATA[782cm -1 > <![CDATA[6 - membered borate ring with BO4 units]]> <![CDATA[720cm -1 > Metaborate chain <![CDATA[666cm -1 > Si-O-Si chain

[0131] For example, in the case where the compound has a Raman spectrum including at 943±25 cm-1 In the case of the Raman spectrum of the belt at -1 , it is preferred that the intensity of the band at -1 is at least 1.5 times, preferably at least 2 times greater than the intensity of the spectrum at

[0132] The lithium borosilicate compound or the doped lithium borosilicate compound can be as described above for the first aspect of the present invention.

[0133] Preferably, the amorphous compound is lithium borosilicate. The lithium borosilicate component can be as described above for the first aspect of the present invention.

[0134] In some embodiments, the amorphous compound is lithium borosilicate or nitrogen-doped lithium borosilicate.

[0135] In some embodiments, the amorphous compound does not include phosphorus.

[0136] Preferably, the amorphous compound has a low electron conductivity. In some embodiments, the amorphous compound has a measured electron conductivity at 25 °C of less than about 1 x 10 -12 S / cm, such as less than about 2 x 10 -13 S / cm measured at 25 °C, such as less than about 1 x 10 -13 S / cm measured at 25 °C, such as less than about 8 x 10 -14 S / cm.

[0137] In some embodiments, the amorphous compound is a thin film. In some embodiments, the thin film has a thickness between 40 nm and 15,000 nm, such as between 50 nm and 10,000 nm, such as between 100 nm and 5,000 nm, such as between 200 nm and 4,000 nm, such as between 300 nm and 3,000 nm.

[0138] Method for manufacturing an electrode

[0139] In a third aspect, the present invention can provide a method for manufacturing a surface-modified electrode by a vapor deposition process, the electrode including an electrode active material, wherein the surface of the electrode is modified by an amorphous lithium borosilicate or doped lithium borosilicate compound, and the method includes:

[0140] (a) providing a vapor source of each constituent element of the amorphous compound, wherein the vapor source includes at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element;

[0141] (b) providing an electrode;

[0142] (c) A stream for transporting the lithium, the oxygen, the boron, the silicon, and optionally the dopant element; and

[0143] (d) Co - depositing the constituent elements from a vapor source onto an electrode, wherein the constituent elements react on the electrode to form an amorphous compound;

[0144] wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic percent, based on the atomic percentages of the combination of lithium, boron, and silicon.

[0145] The method of the third aspect of the present invention may include one or more optional features of the method of the first aspect of the present invention.

[0146] As used herein, the terms "surface - modified" and "whose surface is modified by..." mean that at least a portion of the surface of the electrode is in mechanical or chemical contact with the amorphous compound described herein.

[0147] In some embodiments of the third aspect of the present invention, the step (b) of providing the electrode includes:

[0148] Providing a first separate vapor source for each constituent element of the electrode; and

[0149] Co - depositing the constituent elements from their separate vapor sources onto a substrate, wherein the constituent elements react on the substrate to form the electrode.

[0150] Alternatively, the step (b) of providing the electrode may include fabricating the electrode by a thick - film or thin - film process. These may include, but are not limited to, physical vapor deposition, chemical vapor deposition, doctor blading, tape casting, screen printing, stencil printing, inkjet printing, transfer printing, flexographic printing, jet printing, gravure printing, offset printing, and / or rotary screen printing, whereby the electrode is an integral (monolith) of the electroactive material or a composite comprising: an electroactive material, a binder, an electronic additive, an ionic additive, which are individually or in combination with each other compatible with the boundary temperature and pressure conditions described herein for the synthesis of solid - state electrolyte materials at low temperatures. The binder material may include organic or inorganic materials (or mixtures thereof) that are compatible with the above - mentioned process conditions and have been used to produce thick - film or thin - film composite electrodes either independently of the current collector or on top of the current collector.

[0151] In one embodiment of the third aspect of the present invention, the method is a method for manufacturing a surface-modified negative electrode. In one embodiment of the third aspect of the present invention, the method is a method for manufacturing a surface-modified positive electrode. In one embodiment of the third aspect of the present invention, the method is a method for manufacturing a LiBSiO surface-modified negative electrode. In another embodiment of the third aspect of the present invention, the method is a method for manufacturing a LiBSiO surface-modified positive electrode. In one embodiment of the third aspect of the present invention, the LiBSiO coating is produced by physical vapor deposition as described herein.

[0152] The electrode active material of the electrode is not particularly limited as long as the material allows an amorphous lithium borosilicate or a doped lithium borosilicate compound to attach its surface thereto and is capable of storing and releasing lithium ions. In some embodiments of the third aspect of the present invention, the surface-modified electrode is a surface-modified negative electrode. The negative electrode active material may be selected from Li4Ti5O 12 ; Li; Si; Ge; Sn; Sb; Al; Mg; Bi; Si-M (M = Mg, Al, Sn, Zn, Ag, Fe, Ni, Mn); InSb; metal oxides, including: TiO2, vanadium oxides and molybdenum oxides, Ti, Nb oxides (MgTi2O5, TiNb2O7), SnO, SnO2, Sb oxides or germanates.

[0153] The negative electrode active material used in the battery of the present invention (or in one embodiment of the third aspect of the present invention) may be lithium or a lithiated transition metal oxide, such as a lithium titanium oxide. The negative electrode active material may be a lithium metal alloy, including LiSi, LiSb or LiGe. The negative electrode active material may also be a carbon-containing material (such as activated carbon), a tin-containing material, a silicon-containing material or other materials capable of reversibly inserting lithium ions.

[0154] The negative electrode active material further includes graphite, synthetic graphite, coke, fullerenes, niobium pentoxide, tin alloys, silicon (including amorphous silicon), titanium oxide, tin oxide, and lithium titanium oxide.

[0155] The negative electrode active material containing an elemental carbon material includes graphite, synthetic graphite, coke, fullerenes, carbon nanotubes, other graphite carbons and combinations thereof. Graphite carbon refers to any elemental carbon material containing a large number of graphene sheet domains.

[0156] In one embodiment of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the negative electrode active material includes lithium metal or an alloy thereof. In a further embodiment of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the negative electrode may include a layer of lithium metal or a lithium-aluminum alloy. In another embodiment of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the negative electrode is lithium. In another embodiment of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the negative electrode is a lithium-free anode. In another embodiment of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the negative electrode is a lithium-air anode. In some embodiments of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the negative electrode is lithium.

[0157] In some embodiments of the third aspect of the present invention, the electrode is a lithium-insertion electrode. As used herein, the term "insertion" means that molecules or ions are reversibly included or inserted into a compound having a layered structure. Thus, a lithium-insertion electrode may be an electrode in which lithium ions can be reversibly included or inserted into a layered structure, such as graphite.

[0158] In some embodiments of the third aspect of the present invention, the surface-modified electrode is a surface-modified positive electrode. The positive electrode active material may include a lithiated transition metal compound, such as lithium nickel manganese oxide, lithium nickel vanadium oxide, lithium cobalt vanadium oxide, or lithium cobalt phosphate, such as Li2NiMn3O8, LiNiVO4, LiCoVO4, LiCoPO4, etc. Other examples include lithium nickel phosphate, lithium nickel fluorophosphate, and lithium cobalt fluorophosphate; namely, LiNiPO4, Li2NiPO4F, Li2CoPO4F, etc. The lithium content typically varies depending on the state of charge of the battery. The positive active material may include other oxygen-containing materials, such as oxides, manganates, nickelates, vanadates, phosphates, or fluorophosphates. The positive active material may have the formula Li x M y N z O, where M is selected from Ni, Mn, V, and Co, and N is a heteroatomic species different from M, such as Ni, Mn, V, Co, or P. N may be omitted. The positive active material may also be fluorinated, for example, as a fluorophosphate.

[0159] In one embodiment, the positive electrode active material of the battery of the present invention (or the electrode provided in the embodiment of the third aspect of the present invention) is selected from LiCoO2, FeS2, LiCoPO4, LiFePO4, Li2FeS2, Li2FeSiO4, LiMn2O4, LiMnPO4, LiNiPO4, LiV3O8, LiV6O 13, LiVOPO4, LiVOPO4F, Li3V2(PO4)3, MnO2, MoS3, S, TiS2, TiS3, V2O5, V6O 13 , LiNi 0.5 Mn 1.5 O4, and LiMnNiCoAIO2.

[0160] In another embodiment, the positive electrode active material of the battery of the present invention (or the electrode provided in the embodiment of the third aspect of the present invention) is a high-voltage positive electrode active material. In a further embodiment, the high-voltage positive electrode active material is selected from LiCoPO4, LiNi 0.5 Mn 1.5 O4, LiMnPO4, LiMn2O4, LiCoO2, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2, LiFePO4, LiNiPO4, Li2NiPO4F, Li2CoPO4F, LiMnPO4F, Li2CoSiO4, Li2MnSiO4, FeF3, LiMn 0.8 Fe 0.1 Ni 0.1 PO4, Li 1-x VOPO4 and Li2FePO4F.

[0161] In some embodiments, the electrode comprises a positive electrode active material selected from: LiCoPO4, LiNi 0.5 Mn 1.5 O4, LiMnPO4, LiCoO2, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2, LiFePO4, LiNiPO4, Li2NiPO4F, Li2CoPO4F, LiMnPO4F, Li2CoSiO4, Li2MnSiO4, FeF3, LiMn 0.8 Fe 0.1 Ni 0.1 PO4, Li 1-x VOPO4, and Li2FePO4F.

[0162] Amorphous lithium borosilicate or doped lithium borosilicate compounds can be any of the compounds described above for the first aspect of the present invention. In some embodiments of the third aspect of the present invention, the amorphous compound is lithium borosilicate. In some embodiments of the third aspect of the present invention, the amorphous compound is nitrogen-doped lithium borosilicate.

[0163] In some embodiments of the third aspect of the present invention, an amorphous lithium borosilicate compound or a doped lithium borosilicate compound is provided as a layer on the surface of an electrode. In some embodiments of the third aspect of the present invention, the amorphous compound is deposited on one or more layers supported on a substrate laminate structure such as graphite.

[0164] In some embodiments of the third aspect of the present invention, the electrode is coated with a layer of an amorphous compound (such as LiBSiO) as described herein. In some embodiments of the third aspect of the present invention, the amorphous compound (such as LiBSiO) as described herein is provided as a layer on the surface of the electrode.

[0165] In some embodiments of the third aspect of the present invention, the surface of the electrode is coated with a layer of an amorphous compound (such as LiBSiO) as described herein. This coating can be achieved by first casting (doctor blading) an electrode comprising an electrode active material (and optionally a carbon additive, a polymeric binder, and / or a solvent) on a current collector, and then curing and drying the electrode. The surface of the cast electrode can then have a protective layer of an amorphous compound (such as LiBSiO) deposited thereon. In some embodiments of the third aspect of the present invention, the amorphous compound (such as LiBSiO) completely coats the surface of the electrode. In some embodiments of the third aspect of the present invention, the amorphous compound (such as LiBSiO) partially covers the surface of the electrode.

[0166] In some preferred embodiments of the third aspect of the present invention, the electrode is provided at a temperature below about 180 °C, and the amorphous compound is lithium borosilicate, and the electrode comprises lithium.

[0167] Electrode

[0168] Also described herein are electrodes that have been surface modified. The electrodes are surface modified using the method according to the third aspect of the present invention.

[0169] The electrode comprises an electrode active material, wherein the surface of the electrode is modified by an amorphous lithium borosilicate compound or a doped lithium borosilicate compound as described herein. In some preferred embodiments, the surface of the electrode is modified by a lithium borosilicate compound. The LiBSiO surface modified electrode can have improved stability and / or improved cycling relative to an unmodified electrode, particularly (although not exclusively) when operating in the presence of an adjacent liquid phase electrolyte material.

[0170] In some embodiments, an amorphous compound (e.g., LiBSiO) is deposited as a layer on the electrode material. As a result, the electrode can be coated with a layer of the amorphous compound. In some embodiments, the amorphous compound completely coats the surface of the electrode. In some embodiments, the amorphous compound partially covers the surface of the electrode.

[0171] In some embodiments, the electrode includes a negative electrode active material. The negative electrode material can be as described above with respect to the third aspect of the present invention. In some embodiments, the electrode includes a positive electrode active material. The positive electrode active material can be as described above with respect to the third aspect of the present invention.

[0172] In some preferred embodiments, the electrode is surface-modified at a temperature below 180 °C, and the amorphous compound is lithium borosilicate, and the electrode includes lithium.

[0173] Method for manufacturing a battery

[0174] Another aspect of the present invention provides a method of manufacturing a battery. The method includes depositing an electrolyte of the battery as a layer of an amorphous lithium borosilicate compound or a doped lithium borosilicate compound using the vapor deposition method according to the first aspect described above.

[0175] In some embodiments, the battery is a thin film battery. The thin film battery can be produced by sequentially forming films of all-solid components.

[0176] Battery – The surface of the negative electrode and / or the positive electrode is modified with an amorphous compound

[0177] One aspect of the present invention relates to a battery, which includes: a positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode, wherein at least one of the negative electrode or the positive electrode is a surface-modified electrode, and the surface-modified electrode is as described herein.

[0178] In some embodiments, the surface of at least one of the negative electrode or the positive electrode is modified with an amorphous lithium borosilicate compound or a doped lithium borosilicate compound as described herein.

[0179] In some preferred embodiments, the amorphous compound does not contain phosphorus. In some preferred embodiments, the amorphous compound is lithium borosilicate. In some embodiments, preferably the lithium borosilicate composition consists essentially of a system of lithium oxide in combination with silicon oxide and boron oxide, wherein the lithium borosilicate contains 40 - 65 atomic % lithium, based on the atomic percentages of the combination of lithium, boron, and silicon, and wherein the lithium borosilicate is a glass. In one embodiment, the battery includes a LiBSiO surface-modified negative electrode.

[0180] In one embodiment, the battery includes a positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode, wherein the negative electrode is coated with a layer of an amorphous compound (such as LiBSiO) as described herein. In one embodiment, the battery includes a positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode, wherein the positive electrode is coated with a layer of an amorphous compound (such as LiBSiO) as described herein.

[0181] In one embodiment, the present invention provides a battery comprising: a positive current collector, a positive electrode including a positive electrode active material, an electrolyte, a negative electrode including a negative electrode active material, and a negative current collector, wherein the surface of at least one of the negative electrode or the positive electrode is modified by an amorphous compound (such as LiBSiO) as described herein. In one embodiment, the battery includes a negatively electrode surface-modified with LiBSiO. In one embodiment, the battery includes a positively electrode surface-modified with LiBSiO.

[0182] Both the positive electrode (cathode) and the negative electrode (anode) can be surface-modified by an amorphous compound (such as LiBSiO) as described herein. For example, in another embodiment, the battery includes a negatively electrode surface-modified with LiBSiO and a positively electrode surface-modified with LiBSiO.

[0183] In a further embodiment, the battery is a lithium-ion secondary battery. In another embodiment, the lithium-ion secondary battery is a thin-film battery.

[0184] In one embodiment, the present invention provides a battery comprising: a positive current collector, a positive electrode including a positive electrode active material, an electrolyte, a negative electrode including a negative electrode active material, and a negative current collector, wherein the negative electrode is coated with the amorphous compound of the present invention (such as LiBSiO), for example, an amorphous compound prepared by the method of the first aspect of the present invention. In one embodiment, the battery includes a negatively electrode coated with LiBSiO. In another embodiment, the battery includes a negatively electrode coated with LiBSiO and a positively electrode coated with LiBSiO.

[0185] The electrolyte may include an organic electrolyte, a liquid electrolyte, an ionic liquid, a gel electrolyte, a room-temperature molten salt, or a solid electrolyte. If the electrolyte is liquid or gel, preferably it is a non-aqueous electrolyte. In one embodiment, the electrolyte is an organic electrolyte. In another embodiment, the electrolyte is a liquid electrolyte. In a further embodiment, the liquid electrolyte is a non-aqueous electrolyte. In another embodiment, the electrolyte is a gel electrolyte. In another embodiment, the electrolyte is a molten salt electrolyte. In another embodiment, the electrolyte is a solid electrolyte.

[0186] In a further embodiment, the liquid non-aqueous electrolyte comprises a lithium salt and a non-aqueous solvent. Examples of the lithium salt include LiPF6, LiBF4, lithium bis(trifluoromethanesulfonyl)amide (LiTFSA, LiN(CF3SO2)2), LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiClO4, lithium bis(oxalato)borate (LiBOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)amide (LiFSA, LiN(SO2F)2), and LiCF3CO2. The non-aqueous solvent is capable of dissolving the lithium salt. Examples of the non-aqueous solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetonitrile, propionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, nitromethane, N,N-dimethylformamide, dimethyl sulfoxide, sulfolane, vinylene carbonate, and γ-butyrolactone.

[0187] In some embodiments, the electrolyte comprises an additive. The electrolyte additive can readily and economically modify the electrode-electrolyte interface. In some embodiments, the electrolyte comprises an additive selected from: 4-(trifluoromethyl)-1,3-dioxolan-2-one (TFM-EC), tris(hexafluoroisopropyl) phosphate (HFip), 3-hexylthiophene, LiDFOB, tris(trimethylsilyl) phosphate (TMSP), tris(trimethylsilyl) borate (TMSB), and combinations thereof.

[0188] Battery – The electrolyte is in the form of a layer of an amorphous lithium borosilicate compound or a doped lithium borosilicate compound

[0189] Another aspect of the present invention provides a battery, wherein the battery comprises:

[0190] a positive electrode;

[0191] a negative electrode; and

[0192] an electrolyte;

[0193] wherein the electrolyte is in the form of an amorphous lithium borosilicate compound or a doped lithium borosilicate compound layer deposited on a substrate using the vapor deposition method according to the first aspect of the present invention described above.

[0194] In some embodiments, the negative electrode comprises lithium. In some embodiments, the positive electrode comprises lithium. In some embodiments, the positive electrode comprises a positive electrode active material selected from: LiCoPO4, LiNi 0.5 Mn 1.5 O4, LiMnPO4, LiCoO2, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3O2, LiFePO4, LiNiPO4, Li2NiPO4F, Li2CoPO4F, LiMnPO4F, Li2CoSiO4, Li2MnSiO4, FeF3, LiMn 0.8 Fe 0.1 Ni 0.1 PO4, Li 1-x VOPO4, and Li2FePO4F.

[0195] In some preferred embodiments, the amorphous compound is lithium borosilicate. The amorphous compound can be as described above for any aspect of the present invention.

[0196] In some embodiments, the battery further includes a positive electrode current collector and a negative electrode current collector. In further embodiments, the battery further includes a substrate. In further embodiments, the battery is encapsulated.

[0197] In some embodiments, the battery is a lithium-ion battery. In some embodiments, the battery is a secondary lithium-ion battery. In some embodiments, the battery is a thin-film battery, which includes a positive electrode, an electrolyte, and a negative electrode. In some embodiments, the battery is a all-solid-state battery.

[0198] In some embodiments, the battery is an improved lithium-ion battery, which includes a negative electrode, a positive electrode, and an electrolyte including an amorphous compound (such as LiBSiO) as described herein for any aspect of the present invention, wherein the positive electrode includes a high-voltage positive active material having an electrochemical potential of at least 3.5 V relative to Li / Li + at least 4.0 V relative to Li / Li + at least 4.5 V relative to Li / Li + at least 5.5 V relative to Li / Li + at least 6.0 V relative to Li / Li + or between 6.0 - 8.5 V.

[0199] A Li-ion battery having an amorphous compound electrolyte (such as a LiBSiO electrolyte) as described herein for any aspect of the present invention and a high-voltage positive electrode allows for the development of Li-ion batteries with high energy / power density. Additionally, the amorphous compounds obtained according to the methods described herein or obtainable according to the methods described herein can have very high ionic conductivity and low electrical conductivity, and thus can provide improved performance such as higher power and energy and stable low capacity. For high-voltage operation, another important aspect of the electrolyte properties is redox stability. Improved redox stability improves the cycling performance and lifespan of the batteries of the present invention.

[0200] The negative electrode and the positive electrode can be as described above.

[0201] Each of the ranges described herein can be employed alone or in combination with one or more other component ranges to provide preferred aspects of the present invention.

[0202] Examples

[0203] The present invention will now be described with reference to the following non-limiting examples.

[0204] Experimental methods and materials

[0205] As a function of the lithium content (about 48 - 88 atomic % lithium, based on the components Li, B, and Si), the ionic conductivity of a series of compositions in the LiBSiO system was measured.

[0206] Also as a function of the lithium content (about 47 - 82 atomic % lithium, based on the components Li, B, and Si), the crystallization temperature of a series of compositions in the LiBSiO system was measured.

[0207] In addition, Raman spectra of certain compositions were obtained.

[0208] In this series of experiments, a lithium borosilicate material was formed from the constituent elements lithium, oxygen, and the two glass-forming elements boron and silicon using the method disclosed in WO2015 / 104540, titled "Vapor Deposition Method for Preparing Amorphous Lithium-Containing Compounds" (incorporated herein by reference in its entirety). The lithium borosilicate was made by providing vapor sources of the constituent elements of the compound and co-depositing the constituent elements from the vapor sources onto a substrate heated to 225 °C at a pressure of 2.7x10 -3 to 4.3x10 -3 Pa (2x10 -5 to 3.2x10 -5 Torr). The constituent elements reacted on the substrate to form an amorphous lithium borosilicate compound.

[0209] Deposition was carried out in a physical vapor deposition (PVD) system previously described in the literature (Guerin, S. and Hayden, B. E., Journal of Combinatorial Chemistry 8 (2006) 66 - 73). All samples were deposited using an oxygen plasma source as the source of atomic oxygen (the plasma source converts O₂ (gas) into a stream of oxygen atoms, radicals, and / or ions directed at the substrate). Oxide materials, lithium silicate, and lithium borate require the highest oxidation states of both silicon and boron (4+ and 3+ respectively), and thus using atomic oxygen instead of molecular oxygen removes the dissociation step required to decompose O₂ into 2O and provides highly reactive species to oxidize silicon and boron to their highest oxidation states, as required in the materials Li₄SiO₄ and Li₃BO₃. Lithium was deposited from a Knudsen cell source. Both silicon and boron were deposited from an electron gun (E - Gun) source.

[0210] The deposition rate of lithium was controlled by varying the temperature of the Knudsen source, while the deposition rates of boron and silicon were controlled according to the power of the electron beam power supply. The rate of the source was determined using a quartz crystal microbalance placed directly beneath the substrate on which the film was deposited.

[0211] The substrate used was always a stainless - steel substrate (type ss304). The substrate had the following composition: 9.25 wt% Ni, 19 wt% Cr, 1 wt% Si, 2 wt% Mn, 0.08 wt% C, 0.045 wt% P, 0.03 wt% S, and 68.595 wt% Fe. The substrate had a thickness of 0.51 mm and a diameter of 15.85 mm.

[0212] The elemental composition of the samples was measured by laser ablation inductively coupled plasma mass spectrometry (ICP - MS) using a Perkin Elmer Elan 9000 ICP - MS equipped with a New Wave 213 nm laser. The ICP - MS analysis was carried out with reference to pellets including the NIST610 standard reference material.

[0213] The thickness of the samples was measured by ellipsometry (Woollam M - 200FI Spectroscopic Ellipsometer). Deposition times of 60 to 840 minutes were used to deposit films with thicknesses in the range of 350 to 2688 nm.

[0214] Impedance measurements are made on the deposited material to measure the ionic conductivity of the material. Such impedance measurements are made using a Solartron 1260 Impedance Analyser. The solid electrolyte is sandwiched between a stainless steel or platinum-coated substrate (bottom electrode) and a platinum top electrode. The solid electrolyte continuously covers the bottom electrode while discrete top platinum electrodes are deposited using RF sputtering. The impedance is measured using an AC excitation potential of 150 mV over a frequency range from 1 MHz to 0.01 Hz. The response at each frequency is determined using a 5-second integration time. Seven frequencies are measured per decade at logarithmic intervals between the upper and lower frequency limits.

[0215] The crystallization temperature is measured by monitoring the change in reflectivity of the sample as a function of temperature in an inert atmosphere. This technique is based on the recognition that crystallization events (and other phase changes in the material) are typically associated with a sudden change in reflectivity. It is described, for example, in Guerin, S.; Hayden H.; Hewak, D.W.; and Vian, C., Synthesis and Screening of Phase Change Chalcogenide Thin Film Materials for Data Storage, ACS Comb. Sci. 2017, 19, 478 - 491: This article describes techniques related to phase change storage materials, but it is also applicable to a range of other amorphous materials and glasses.

[0216] To measure the crystallization temperature, the sample is mounted on a copper block with two embedded cartridge heaters that are operated via a Eurotherm 3508 controller, and the assembly is placed in a sealed stainless steel chamber with a top window. The sample is held in an inert argon atmosphere and heated at a rate of 5 °C per minute. Uniform white light is provided by a halogen lamp and a light diffuser, and the image of the sample is recorded using an off-axis CCD camera (Lumenera Infinity 2 - 1M) at set time intervals of 12 seconds, providing one photograph per degree of temperature change. Images of the sample are recorded during the heating process until a sudden increase in reflectivity is observed, indicating crystallization.

[0217] Results: Ionic conductivity

[0218] Figure 2A and 2B A ternary diagram showing the lithium borosilicate system is presented, where the ionic conductivity of lithium borosilicate is given as a function of composition (the ternary diagram shows only the composition as a function of the amounts of lithium, boron, and silicon present: it is assumed that oxygen is present in the amounts necessary to maintain electrical neutrality).

[0219] It is known from the prior art that lithium borosilicates containing high levels of lithium (e.g., greater than 75 atomic %) exhibit high ionic conductivities of about 1x10 -6 S / cm or higher. As the lithium content decreases from these levels, the ionic conductivity also generally shows a downward trend. However, surprisingly, in the compositional region of about 45 - 65 atomic % lithium; 15 - 35 atomic % boron; and 10 - 25 atomic % silicon, anomalously high levels of ionic conductivity are observed, which is contrary to the general trend of decreasing ionic conductivity with decreasing lithium content. Table 3 shows the ionic conductivity values for specific compositions in the region of anomalously high ionic conductivity (given as atomic % based on the combined atomic percentages of lithium, silicon, and boron).

[0220] Table 3

[0221]

[0222]

[0223] Results: Crystallization temperature

[0224] Figure 3 A ternary diagram showing the lithium borosilicate system is presented, where the crystallization temperature of the lithium borosilicate is given as a function of composition (the ternary diagram shows only the composition as a function of the amounts of lithium, boron, and silicon present: it is assumed that oxygen is present in the amount necessary to maintain electrical neutrality).

[0225] As can be Figure 3 seen, there is a general trend for the crystallization temperature to increase as the lithium content decreases. Thus, for example, at a lithium content of about 70 atomic %, the crystallization temperature is typically in the range of 300 - 400 °C, while at a lithium content of about 60 atomic % or less, the crystallization temperature is generally above about 420 °C.

[0226] The higher crystallization temperatures observed at lower lithium contents are thought to provide more thermally stable compounds that can better withstand temperatures, for example, experienced during the manufacture of solid-state batteries. Crystallization of lithium borosilicate compounds is generally undesirable as it is thought to cause a significant decrease in the ionic conductivity of the compound, thereby reducing its suitability as an electrolyte or electrode surface modifier.

[0227] Table 4 shows the crystallization temperature values for specific compositions.

[0228] Table 4

[0229]

[0230]

[0231] Results: Raman spectroscopy

[0232] The Raman spectrum obtained for lithium borosilicate comprising 57.98 atomic % lithium, 27.57 atomic % boron, and 14.45 atomic % silicon (based on the atomic percentages of the combination of lithium, boron, and silicon) is shown in Figure 4 .

[0233] The band at about 868 cm -1 indicates the presence of the orthosilicate component, while the band at about 943 cm -1 indicates the presence of the orthoborate component. These structural units are thought to facilitate the mobility of lithium throughout the lithium borosilicate glass. In contrast, the spectral intensity at about 782 cm -1 is much lower, indicating a relatively low proportion of six-membered rings with BO4 units in the lithium borosilicate glass. It is thought that these structural units cannot improve the mobility of lithium to the same extent as the orthosilicate and orthoborate units.

[0234] All publications mentioned in the above specification are incorporated herein by reference. Various changes and variations of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the present invention has been described in connection with specific preferred embodiments, it should be understood that the claimed invention should not be unduly limited to such specific embodiments. Indeed, various changes to the described modes for carrying out the invention that are obvious to those skilled in the art of chemistry, materials science, or related fields are intended to be within the scope of the appended claims.

Claims

1. A vapor deposition method for preparing an amorphous lithium borosilicate or a doped lithium borosilicate compound, the method comprising: Provide a vapor source for each constituent element of the compound, wherein the vapor source includes at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element; Transport a stream of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and Co-deposit the constituent elements from the vapor source onto a substrate, wherein the constituent elements react on the substrate to form an amorphous compound; wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

2. The vapor deposition method according to claim 1, wherein the lithium borosilicate or the doped lithium borosilicate compound has a lithium content of 63 atomic % or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

3. The vapor deposition method according to claim 2, wherein the lithium borosilicate or the doped lithium borosilicate compound has a lithium content of 60 atomic % or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

4. The vapor deposition method according to any one of claims 1 - 3, wherein the lithium borosilicate or the doped lithium borosilicate compound has a lithium content of at least 45 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

5. The vapor deposition method according to any one of claims 1 - 3, wherein the lithium borosilicate or the doped lithium borosilicate compound has a boron content in the range of 1 - 50 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

6. The vapor deposition method according to claim 5, wherein the lithium borosilicate or the doped lithium borosilicate compound has a boron content of at least 10 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

7. The vapor deposition method according to claim 5, wherein the lithium borosilicate or the doped lithium borosilicate compound has a boron content of 45 atomic % or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

8. The vapor deposition method according to any one of claims 1 - 3, wherein the lithium borosilicate or the doped lithium borosilicate compound has a silicon content in the range of 1 - 30 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

9. The vapor deposition method according to claim 8, wherein the lithium borosilicate or the doped lithium borosilicate compound has a silicon content of at least 5 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

10. The vapor deposition method according to claim 8, wherein the lithium borosilicate or the doped lithium borosilicate compound has a silicon content of 25 atomic % or less, based on the atomic percentages of the combination of lithium, boron, and silicon.

11. The vapor deposition method according to any one of claims 1 - 3, wherein the amorphous compound is a lithium borosilicate compound consisting essentially of a system of lithium oxide in combination with silicon oxide and boron oxide.

12. The vapor deposition method according to any one of claims 1-3, wherein the composition of the lithium borosilicate compound or the doped lithium borosilicate compound is located in the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 51 atomic % Li - 32 atomic % B - 17 atomic % Si; 46 atomic % Li - 42 atomic % B - 12 atomic % Si; and 52 atomic % Li - 38 atomic % B - 10 atomic % Si; wherein the atomic percentages of lithium, boron, and silicon are each based on the percentages of the combination of lithium, boron, and silicon.

13. The vapor deposition method according to any one of claims 1-3, wherein the composition of the lithium borosilicate compound or the doped lithium borosilicate compound is located in the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 50 atomic % Li - 39 atomic % B - 11 atomic % Si; 46 atomic % Li - 42 atomic % B - 12 atomic % Si; 51 atomic % Li - 32 atomic % B - 17 atomic % Si; and 59 atomic % Li - 18 atomic % B - 23 atomic % Si; wherein the atomic percentages of lithium, boron, and silicon are each based on the percentages of the combination of lithium, boron, and silicon.

14. The vapor deposition method according to any one of claims 1-3, wherein the composition of the lithium borosilicate compound or the doped lithium borosilicate compound is located in the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 53 atomic % Li - 32 atomic % B - 15 atomic % Si; and 52 atomic % Li - 38 atomic % B - 10 atomic % Si; wherein the atomic percentages of lithium, boron, and silicon are each based on the percentages of the combination of lithium, boron, and silicon.

15. The vapor deposition method according to any one of claims 1-3, wherein the composition of the lithium borosilicate compound or the doped lithium borosilicate compound is located in the region defined by: 64 atomic % Li - 26 atomic % B - 10 atomic % Si; 63 atomic % Li - 21 atomic % B - 16 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 56 atomic % Li - 32 atomic % B - 12 atomic % Si; and 51 atomic % Li - 32 atomic % B - 17 atomic % Si; wherein the atomic percentages of lithium, boron, and silicon are each based on the percentages of the combination of lithium, boron, and silicon.

16. The vapor deposition method according to any one of claims 1-3, wherein the composition of the lithium borosilicate compound or the doped lithium borosilicate compound is located in the region defined by: 60 atomic % Li - 27 atomic % B - 13 atomic % Si; 59 atomic % Li - 18 atomic % B - 23 atomic % Si; 56 atomic % Li - 32 atomic % B - 12 atomic % Si; and 51 atomic % Li - 32 atomic % B - 17 atomic % Si; wherein the atomic percentages of lithium, boron, and silicon are each based on the percentages of the combination of lithium, boron, and silicon.

17. The vapor deposition method according to any one of claims 1-3, wherein the composition of the lithium borosilicate compound or the doped lithium borosilicate compound is located in the region defined by: 60 atomic % Li - 27 atomic % B - 13 atomic % Si; 60 atomic % Li - 25 atomic % B - 15 atomic % Si; 59 atomic % Li - 22 atomic % B - 19 atomic % Si; 56 atomic % Li - 32 atomic % B - 12 atomic % Si; and 53 atomic % Li - 32 atomic % B - 15 atomic % Si; wherein the atomic percentages of lithium, boron, and silicon are each based on the percentages of the combination of lithium, boron, and silicon.

18. The vapor deposition method according to any one of claims 1-3, wherein the vapor source of oxygen is a vapor source of atomic oxygen or molecular oxygen.

19. The vapor deposition method according to any one of claims 1-3, wherein the substrate comprises a surface layer supported on a bulk substrate element.

20. A composition comprising an amorphous lithium borosilicate or a doped lithium borosilicate compound, wherein the composition is obtained by depositing the amorphous compound on a substrate using a vapor deposition method according to any one of claims 1 - 3, and further wherein the ionic conductivity of the compound is at least about 1 x 10 -7 S / cm at 25 °C.

21. A composition comprising an amorphous lithium borosilicate or a doped lithium borosilicate compound, wherein the composition is obtained by depositing the amorphous compound on a substrate using a vapor deposition method according to any one of claims 1 - 3, and further wherein the compound has a crystallization temperature of at least 350 °C.

22. A composition comprising an amorphous lithium borosilicate or a doped lithium borosilicate compound, wherein the composition is obtained by depositing the amorphous compound on a substrate using a vapor deposition method according to any one of claims 1 - 3, and further wherein the compound has a Raman spectrum comprising one or more bands selected from: 839 ± 25 cm -1 ; 868 ± 25 cm -1 ; 918 ± 25 cm -1 ; and 943 ± 25 cm -1 .

23. The composition according to claim 22, wherein the compound has a Raman spectrum comprising a band at 943 ± 25 cm -1 , and the intensity of the band at 943 ± 25 cm -1 is at least 1.5 times the intensity of the spectrum at 782 cm -1 .

24. A method of manufacturing a surface - modified electrode by a vapor deposition process, the electrode comprising an electrode active material, wherein the surface of the electrode is modified by an amorphous lithium borosilicate or a doped lithium borosilicate compound, and the method comprises: (a) Provide a vapor source for each constituent element of the amorphous compound, wherein the vapor source includes at least a lithium source, an oxygen source, a boron source, and a silicon source, and optionally a source of at least one dopant element; (b) Provide an electrode; (c) Transport a stream of the lithium, the oxygen, the boron, and the silicon, and optionally the dopant element; and (d) Co - deposit the constituent elements from a vapor source onto an electrode, where the constituent elements react on the electrode to form an amorphous compound; wherein the amorphous lithium borosilicate or doped lithium borosilicate compound has a lithium content in the range of 40 - 65 atomic %, based on the atomic percentages of the combination of lithium, boron, and silicon.

25. The method according to claim 24, wherein the vapor source further comprises a nitrogen source, and the amorphous compound is a nitrogen - doped lithium borosilicate.

26. The method according to claim 24 or 25, wherein the amorphous compound is provided as a layer on the surface of the electrode.

27. A battery, comprising: An electrolyte; A negative electrode; And A positive electrode; wherein at least one of the negative electrode or the positive electrode is a surface - modified electrode obtained by the method according to claim 24 or 25.

28. A method of manufacturing a battery, comprising depositing an electrolyte of the battery as a layer of amorphous lithium borosilicate or a doped lithium borosilicate compound using a chemical vapor deposition method according to any one of claims 1 - 3.

29. A battery, comprising: A positive electrode; A negative electrode; And An electrolyte; wherein the electrolyte is in the form of a layer of an amorphous lithium borosilicate or doped lithium borosilicate compound deposited on a substrate using the vapor deposition method according to any one of claims 1 - 3.

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