SELECTIVE Zn (101) FACET GROWTH AND PLATING LOCATION ENGINEERING FOR FAST KINETIC AND SUSTAINABLE ANODE

Abstract

An aqueous zinc-ion electro-chemical cell may include an anode. The anode may include an electrode and an interphase layer disposed on the electrode. The interphase layer may include a non-stoichiometric tin oxide (SnOx) where 1 < x <= 1.2. The interphase layer may guide Zn²⁺ ions to plate beneath the interphase layer along the Zn (101) crystallographic orientation.

Description

PATENTAtty Dkt. No. 70910-02SELECTIVE Zn (101) FACET GROWTH AND PLATING LOCATION ENGINEERING FOR FAST KINETIC AND SUSTAINABLE ANODECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 737,639 filed December 21 , 2024, the entirety of which is herein incorporated by reference.TECHNICAL FIELD

[0002] This disclosure relates to zinc ion batteries and, in particular, to anode modification of zinc ion batteries.BACKGROUND

[0003] Aqueous zinc ion batteries (ZIBs) have emerged as promising candidates for grid-level energy storage due to their high theoretical capacity, resource abundance, and environmental safety. However, the practical deployment of ZIBs is hindered by several challenges associated with the zinc anode, including uncontrolled dendrite growth, hydrogen evolution reaction (HER), and corrosion, which collectively limit reversibility and cycle life. These issues are exacerbated under conditions requiring high zinc utilization ratios (ZUR), which are essential for achieving low negative-to-positive (N / P) capacity ratios comparable to commercial lithium-ion batteries.

[0004] The crystallographic orientation of plated zinc plays a critical role in determining the anode's electrochemical behavior and susceptibility to side reactions. Conventional strategies have focused on inducing Zn2+plating along the (002) facet, which exhibits lower reactivity with water and can suppress dendrite formation. Materials such as graphene, metallic sulfides, MXenes, and metal-organic frameworks have been employed to promote (002)-oriented growth, leading to improved reversibility and reducedPATENTAtty. Dkt. No. 70910-02 parasitic reactions. Additional approaches, including separator modifications and electrolyte additives, have also been used to regulate Zn2+plating orientation.

[0005] Despite these advances, (002)-oriented plating is associated with sluggish ion transfer kinetics and weak Zn-Zn bonding, resulting in lattice distortion and increased polarization during cycling. Furthermore, the plated zinc often deviates from the (002) facet, compromising structural integrity and efficiency. Recent research suggests that alternative orientations, such as the (101 ) facet, may offer faster growth rates and stronger Zn-Zn bonding, provided that the plated zinc is isolated from direct contact with water.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The embodiments may be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale. Moreover, in the figures, like-referenced numerals designate corresponding parts throughout the different views.

[0007] FIG. 1 illustrates an example of an anode in an electrochemical cell.

[0008] FIG. 2 illustrates an example of an anode in an electrochemical cell after the anode is exposed to electrolyte and after Zn plating.

[0009] FIG. 3 illustrates how plated Zn predominantly exhibits three crystallographic facets, including (002), (100), and (101 ).

[0010] FIG. 4 illustrates an example of dangling bonds of the various Zn facets aligned with P-Type SnO.

[0011] FIG. 5 illustrates an example of an electrochemical cell after plating without a SnOx interphase layer.

[0012] FIG. 6 illustrates an example of an electrochemical cell after plating with a SnOx interphase layer.

[0013] FIG. 7A-B illustrate an example of an electrochemical cell including an anode having an electrode with an interphase layer.PATENTAtty. Dkt. No. 70910-02DETAILED DESCRIPTION

[0014] This disclosure provides an anode and related manufacturing methods that provide Zn2+ plating with a regulated orientation of (101 ) located underlying the artificial interphase for sustained aqueous Zn ion batteries. In traditional batteries, Zn is a hexagonal close-packed (hep) metal. The traditional artificial interphase was designed to induce the (002)-oriented Zn2+plating overlying the artificial interphase due to the high resistance of Zn (002) to water corrosion and hydrogen evolution reaction (HER). However, plated Zn on Zn (002) is easy to deviate from the original lattice growth, resulting in lattice distortion, due to the weak bonding effect of Zn (002) on plated Zn atoms. Besides, the slow mass (i.e., Zn2+) transfer at Zn (002) can lead to sluggish kinetics for Zn2+plating / stripping during the battery cycling.

[0015] Although the stability of the dominant crystal planes follows the order Zn (002) > Zn (100) > Zn (101 ), the Zn2+transfer kinetics follow the opposite trend: Zn (101 ) > Zn(100) > Zn (002). In order to utilize the fast Zn2+transfer kinetics of Zn (101 ) while maintaining the electrochemical stability during Zn2+plating / stripping, this disclosure provides a SnOx interphase on the anode of Zn batteries, by which the Zn2+plating location was guided underlying the interphase (i.e., SnOx) with a regulated (101 ) orientation. Thus, the water-triggered parasitic reactions have been eliminated due to the direct isolating of the (101 )-oriented Zn from water molecules. Additionally, the faster Zn2+transfer kinetics of Zn (101 ) and rapid ion channels of SnOx interphase enables low polarization and mitigated hysteresis during the battery cycling. Besides, the Zn (101 ) plane exhibits a stronger interaction with Zn ions compared to the Zn (002) plane, preventing lattice distortion at high Zn plating amounts and resulting in well-aligned Zn(101 ) planes. This SnOx interphase shows great potential for modifying the anode towards fast-charging Zn batteries with a long cycle life.

[0016] Zn ion batteries (ZIBs) with mild aqueous electrolytes (i.e., ZnSO4) have been considered grid-level energy storage solutions due to their high theoretical capacity (820 mAh g-1), resource abundance, and eco-friendliness.

[0017] However, the uncontrollable Zn dendrite growth, hydrogen evolution reaction (HER), and corrosion, severely limit the reversibility and lifespan of ZIBs. These issuesPATENTAtty. Dkt. No. 70910-02 are more detrimental in practical ZIBs, which require a negative / positive (N / P) capacity ratio lower than 1.08 (refer to the commercialized Lithium-ion batteries, LIBs). A Zn utilization ratio (ZUR) higher than 80% is the prerequisite to realize this low N / P ratio. The low ZUR and poor reversibility significantly undermine the advantages of ZIBs compared to alternative technologies such as lithium-ion and sodium-ion batteries. The characteristics of plated Zn, which are normally dominated by the crystallographic (002),(100), and (101 ) facets of hexagonal close-packed (hep) Zn, are highly correlated to the Zn stripping / plating behaviors and concomitant side reactions. According to the Gibbs- Curie-Wulff theorem, the (002) facet of Zn metal has a lower reactivity with water and a slower growth rate due to the lower surface energy compared to that of the (001 ) and(101 ) facets. Therefore, inducing the crystalline orientation of plated Zn along the (002) plane may effectively inhibit dendritic growth, HER, and corrosion, thereby enhancing the high ZUR performance.

[0018] Archer et al. employed graphene as the anode to induce the (002) oriented growth of Zn2+plating, leading to an enhanced Zn2+stripping / plating reversibility. Subsequently, a series of materials such as metallic sulfides, MXenes, and Metal-organic frameworks followed the work to modulate the orientation of plated Zn along the (002) facets, which suppressed the formation of dendrites to some extent. In addition to the anode modifications, separator alterations (e.g., by sulfonic cellulose coating) and the adoption of electrolyte additives (e.g., anionic surfactants) have also been demonstrated to regulate Zn2+plating along the (002) facet. The universal mechanism of these approaches is to reduce the nucleation energy barrier of Zn (002) and hence promote the Zn growth with the (002) orientation.

[0019] Therefore, it is important to note that dendrite growth can be suppressed by (002)-oriented Zn2+plating. Nevertheless, the slower growth rate of Zn (002) compared to Zn (100) and (101 ) provokes a larger polarization during Zn stripping / plating, which negatively impacts battery performance. In addition, the plated Zn orientation easily deviates from the (002) facet resulting in significant lattice distortion, due to the weak bonding between the (002) facet and the plated Zn atoms, further compromising structural integrity and efficiency.PATENTAtty. Dkt. No. 70910-02

[0020] Provided that other Zn orientations are not directly exposed to water, the above issues may be addressed by utilizing other Zn orientations, such as preferably grown (101 ), which exhibit faster growth rates and stronger Zn-Zn bonding to maintain the desired facet.

[0021] To achieve such a goal, at least the following technical advancements are provided. First an artificial interphase that ensures fast Zn2+diffusion and electron shielding allows the Zn2+plating underlying the interphases, preventing the plated Zn from direct contact with water. Second, selective Zn orientation (in this study (101 )) may be achieved by saturating the Zn dangling bonds of the selected (101 ) facet of Zn. These technical advancements were based on the observations that Zn2+plating is governed by Zn2+diffusion and electron reduction. The rapid diffusion of Zn2+, coupled with limited electron availability within the material, prevents the reduction of Zn2+at the interphase. This allows Zn2+to migrate through the interphase until the ions reach its end, where Zn begins plating underlying the interphase upon encountering an electron source, the Zn electrode. These technical advancements were also based on the observations that the existence of dangling bonds is directly associated with surface energy, which raises the nucleation energy barrier, and consequently limits the growth of crystalline phases.

[0022] FIG. 1 illustrates an example of an anode 102 in an electrochemical cell 100. The anode 102 may include an electrode 104 and an interphase layer 106 disposed on the electrode 104.

[0023] The electrode 104 may include a current collector. For example, the electrode 104 may include a metal foil. Possible materials for the electrode 104 may include Zn, Cu, Al metal. The electrode thickness may be between 5 and 30 pm.

[0024] The interphase layer 106 may include a crystalline structure with facets including (001 ) and (1 10), which interact strongly with the Zn (101 ) facet to reduce surface energy and promote preferential zinc plating along the (101 ) orientation beneath the interphase layer 106. The interphase layer 106 may include a non-stoichiometric tin oxide (SnOx).

[0025] As used herein, the term “facet” refers to a crystallographic plane that forms on the surface of a crystalline material, expressed by Miller indices such as (101 ), (002), orPATENTAtty. Dkt. No. 70910-02(100). These indices denote the orientation of the plane relative to the crystal lattice axes and are determined by the intercepts of the plane with the unit cell dimensions. Each facet exhibits distinct physical and chemical properties, including surface energy, atomic arrangement, and reactivity, which influence growth behavior and electrochemical performance. For example, in hexagonal close-packed zinc, the (002) facet has a lower surface energy and slower growth rate, whereas the (101 ) facet exhibits higher surface energy and faster ion transport characteristics. Control over facet exposure during metal plating or deposition can significantly affect dendrite formation, plating uniformity, and overall electrode stability in electrochemical systems.

[0026] FIG. 2 illustrates an example of an anode 102 in an electrochemical cell 100 after the anode is exposed to electrolyte 202 and after Zn plating. The electrolyte 202 may be an aqueous electrolyte and using zinc-based salts including, but not limited to, zinc sulfate (ZnSO4), zinc chloride (ZnCI2), zinc triflate (Zn(CF3SO3)2) dissolved in water.

[0027] The interphase layer 106 may guide Zn2+ions to form zinc plating 204 beneath the interphase layer 106 oriented along the Zn (101 ) crystallographic orientation. The oxygen-deficient composition of the interphase layer 106 introduces lattice defects and oxygen vacancies that enhance ionic conductivity, enabling rapid Zn2+migration through the layer while restricting electron transfer. This configuration isolates plated zinc from direct contact with aqueous electrolyte, thereby suppressing hydrogen evolution and corrosion reactions. In some embodiments, the interphase layer 106 exhibits a contact angle greater than 100° and an ionic conductivity at least 100 times greater than that of stoichiometric SnO2, ensuring improved plating kinetics and cycling stability under high current densities. In some examples, the thickness of the interphase layer 106 may be between about 50 nm and 100 nm.

[0028] The range of non-stoichiometric oxide content in oxygen-deficient SnOx contemplated in some technical advancements disclosed herein is 1 < x <= 1 .2. Various examples and embodiments included in this disclosure, the stoichiometric coefficient x is 1.17, but this should not be interpreted as strictly limiting. The range of 1 < x < 1 .2 for the non-stoichiometric tin oxide SnOx is selected because compositions in this interval retainPATENTAtty. Dkt. No. 70910-02 a p-type, layered SnO-like structure and therefore exhibit essentially the same key functional properties that are relevant to the present technical advancements, (i) efficient Zn2+ ion transport across the interphase, (ii) formation of a desirable Schottky contact with Zn metal, and (iii) selective saturation of dangling bonds on the Zn (101 ) surface. Within the compositional window of 1 < x < 1.2, SnOx maintains this p-type layered structure, so one of ordinary skill in the art would reasonably expect these three properties to remain substantially similar across the entire range.

[0029] An oxygen-deficient SnOx (with x <= 1 .2) exhibits a crystalline structure with well-defined facets such as (001 ) and (1 10). This structure enables strong interaction with the Zn (101 ) facet, reducing its surface energy and promoting zinc plating along the (101 ) orientation. As a result, Zn deposits beneath the interphase layer 106 in a controlled manner, forming a preferentially oriented (101 ) structure. In contrast, an oxygen-rich tin oxide with x > 1 .2 tends to have an amorphous structure lacking distinct facets. While it can strongly adsorb Zn ions, it presents a significantly higher migration barrier compared to oxygen-deficient compositions, which limits ion transport. Consequently, Zn plating occurs on top of the interphase layer 106, favoring the Zn (002) orientation rather than (101 ), leading to overlying deposition without the desired facet control.

[0030] FIG. 3 shows the plated Zn predominantly exhibits three crystallographic facets, including (002), (100), and (101 ), each associated with distinct atomic arrangements and growth behaviors. Plating on the (002) basal plane promotes vertically aligned columnar Zn deposition. Plating on the (101 ) plane leads to tilted alignment. Plating on the (100) facet generates a lateral stacking configuration. As described herein, the interphase directs ZN plating along the 101 plane.

[0031] FIG. 4 illustrates an example of dangling bonds of the various Zn facets aligned with P-Type SnO of the interphase layer. P-type SNO selectively saturates dangling bonds at Zn (101 ). However, P-type SNO cannot saturate dangling bonds at Zn (100) and Zn (002).

[0032] Tthe interphase layer 106 may include oxygen atoms capable of forming dative bonds with zinc atoms at the Zn (101 ) facet of the electrode. These dative bonds saturatePATENTAtty Dkt. No. 70910-02 dangling bonds present on the Zn (101 ) surface, thereby reducing surface energy and facilitating preferential nucleation and growth of zinc along the (101 ) orientation.

[0033] FIG. 5 illustrates an example of an electrochemical cell after plating without the SnOx interphase layer described herein. As Zn dendrites form on the anode, the orientation of plated Zn is not regulated. Water molecules can direct contact the electrod leading to the formation of by-products and HER.

[0034] FIG. 6 illustrates an example of an electrochemical cell after plating with the SnOx interphase layer described herein. The orientation of the plated Zn is regulated along Zn (101 ). The zinc plating 204 formed beneath the artificial interphase layer includes a compact, highly oriented metallic zinc deposit with a predominant (101 ) crystallographic orientation and is isolated from water, thereby avoiding HER. This plating occurs directly on the electrode, underlying a thin (~70 nm) crystalline SnOx interphase that is engineered for high ionic conductivity and electron-blocking properties. During electrochemical cycling, Zn2+ions migrate through the SnOx interphase and are reduced at the interface with the underlying zinc, resulting in the formation of a dense, well-aligned Zn(101 ) layer. The interphase effectively isolates the plated zinc from direct contact with the electrolyte, thereby suppressing water-induced corrosion and hydrogen evolution reactions. The underlying Zn(101 ) plating exhibits enhanced ion transfer kinetics, reduced nucleation overpotential, and improved cycling stability, contributing to a high zinc utilization ratio and superior electrochemical performance in aqueous zinc ion batteries.

[0035] The resultant, the SnOx interphase layer 106 allows (101 )-oriented Zn2+ plating, which supports faster mass (Zn2+) transfer compared to (002)-oriented plating, thereby enhancing battery cycling kinetics. Additionally, the Zn (101 ) plane exhibits a stronger interaction with Zn ions, promoting well-aligned, oriented Zn (101 ) plating even at high Zn plating amounts. Since this Zn plating occurs underlying the SnOx interphase, it remains isolated from water, inhibiting parasitic reactions (i.e., water-induced corrosion and HER). Besides, the ultra-thin SnOx interphase with high ionic conductivity provides fast ion channels for Zn ion migration, making it more suitable for practical applications (higher volumetric specific energy) because the thickness of the artificial interphase is generally larger than 1000 nm. Furthermore, the SnOx interphase can be applied to other anodesPATENTAtty Dkt. No. 70910-02(e.g., Cu foil) to improve the electrochemical performance of modified anodes in various battery systems, such as Zn-free anode configurations.

[0036] FIG. 7A-B illustrate an example of an electrochemical cell 100 including an anode 102 having an electrode 104 with an interphase layer 106. FIG. 3A illustrates an example of the electrochemical cell 100 before plating and FIG. 3B illustrates an example of the electrochemical cell 100 after plating. The electrochemical cell also includes a cathode 302. The anode 102 and cathode 302 are placed in a zinc-based aqueous electrolyte 202.

[0037] The interphase layer may include a non-stoichiometric tin oxide (SnOx) where 1 < x <= 1.2 such that the interphase layer guides Zn2+ions to plate beneath the interphase layer along the Zn (101 ) crystallographic orientation. In some examples, the interphase layer has a thickness between about 50 nm and 100m. In some examples, the interphase layer is formed by magnetron sputtering of a tin target in an oxygen / argon atmosphere, followed by annealing. In some examples, the interphase layer is hydrophobic and isolates the electrode from water in an electrolyte. In some examples, the interphase layer comprises dative bonds at the interface with the electrode, saturating dangling bonds of the Zn (101 ) facet. The electrochemical cell 100 may include additional or alternative examples of the anode 102, which are described herein.

[0038] It should be appreciated that the electrochemical cell 100 may be included in a battery, and the battery may have one or more electrochemical cells. Accordingly, the electrochemical cell 100 shown in FIGs 3A-B may also be referred to as a battery. However, in other examples, the battery may have multiple electrochemical cell.

[0039] Manufacturing

[0040] To manufacture the anode, an electrode may be provided. The electrode may be a thin foil, such as a Zn Foil or a Cu foil. The electrode may be polished to remove a native oxide layer. Then, a thin layer of tin oxide (SnOx) may be deposited onto the polished electrode. The deposition may be performed using, for example, magnetron sputtering.

[0041] The deposition may involve saturating dangling bonds at Zn (101 ) via constructing SnOx interphase on the as-polished electrode to reduce the surface energyPATENTAtty. Dkt. No. 70910-02 of Zn (101 ). A metal Sn target was employed with O2 as the reactive sputter gas. The sputtering chamber was may be pumped down toward a base pressure under 2x10-7 Torr. The electrode was rotated (i.e. at 5 rpm) during the depositions to ensure a uniform and homogeneous deposition. The SnOx interphase was engineered by varying oxygen volume potential in the sputter gas (O2 / Ar). The optimized volume potential of O2 / Ar is 13.5 / 86.5 for SnO1.17.

[0042] The tin oxide-coated zinc electrode may be annealed for a duration sufficient to induce crystallization of the SnOx interphase. The annealing process may facilitate tuning the crystalline information and built-in electrostatic interactions of SnOx. The Zn2+ plating location may be adjusted by controlling the polarity and ionic conductivity of the SnOx. In various experimentation, the electrode with the SnOx interphase was heated at 400 °C in the air-ambient for 4 hours to induce a crystallized SnO phase and p-type conductivity.

[0043] Then, the zinc anode may be assembled an electrochemical cell comprising an electrolyte. The zinc platin may form beneath the interphase later in response to cycling the electrochemical cell.

[0044] The SnOx interphase enables (101)-oriented Zn2+ plating, which supports faster mass (Zn2+) transfer compared to (002)-oriented plating, thereby enhancing battery cycling kinetics. Additionally, the Zn (101 ) plane exhibits a stronger interaction with Zn ions, promoting well-aligned, oriented Zn (101 ) plating even at high Zn plating amounts. Since this Zn plating occurs underlying the SnOx interphase, it remains isolated from water, inhibiting parasitic reactions (i.e., water-induced corrosion and HER). Besides, the ultra-thin SnOx interphase (~70 nm) with high ionic conductivity provides fast ion channels for Zn ion migration, making it more suitable for practical applications (higher volumetric specific energy) because the thickness of the artificial interphase is generally larger than 1000 nm. Furthermore, the SnOx interphase can be applied to other anodes (e.g., Cu foil) to improve the electrochemical performance of modified anodes in various battery systems, such as Zn free anode configurations.

[0045] ExperimentationPATENTAtty. Dkt. No. 70910-02

[0046] Various experimentation and validation was performed for this disclosure. The experimentation and validation was performed using non-limiting embodiments. For example, in various experimentation, SnOi.i? was tested to yield various experimental results. The manipulated Zn2+plating underlying SnOi.17 eliminates HER and corrosion by isolating the highly reactive (101 ) Zn from water, which enables sustainable Zn2+plating / stripping, therefore ensuring superior reversibility under high current densities and high ZUR conditions. The SnOi.17 interphase characterization and the comparison with SnOi.92 validate our hypotheses, which helps to develop an engineering approach to achieve enhanced reversibility and kinetics for Zn anode applications. The Zn anode modified with SnOi.17 interphase demonstrates outstanding electrochemical performance in the half-cell tests, allowing for stable cycling for more than 600 hours (20 mA cm-2, 20 mAh cm-2) with a nucleation overpotential of 72 mV and 800 hours at a high ZUR of 91 .5% with a nucleation overpotential of 43 mV. This performance is significantly enhanced, compared to the SnOi.92 counterpart, which deposits Zn overlying the artificial interphase (i.e., SnOi.92) along the (002) facet. The SnOi.92-modified anode sustained cycling for only 140 hours (at 20 mAh cm-2) with an overpotential of 124 mV and 350 hours (high ZUR of 91.5%) with a polarization voltage of 68 mV. The sulfur cathode, MnC cathode, and ZnMn2O4 cathode were selected to pair with (i) commercial Zn foil (40 pm) as the fullcell performance evaluation under high plating / stripping, (ii) ultrathin Zn foil (2.8 pm) for low N / P ratios, and (iii) Cu foil as an Zn free anode condition. The anode modified by SnOi.17 interphase demonstrated capacity retention of 95.2% and 77.4% when paired with PEDOT@S and MnO2 cathodes after 600 and 400 cycles, respectively. Noteworthy, in an Zn free anode system, the anode modified by SnOi.17 interphase maintained as high as 87.6%, compared to its original capacity after 200 cycles in a configuration of ZnMn2O4||SnOi.i7@Cu, which far surpasses the 30.9% of the ZnMn2O4||SnOi.92@Cu cell after 200 cycles.

[0047] Morphology. The morphology of the pristine electrode (using a Zn substrate as example) and the SnOx interphase-modified Zn anode exhibited a smooth, clean surface compared to the pristine Zn, indicating the uniform coating of the SnOx interphase on the metallic Zn. The element distribution and the thickness of the SnOx interphase werePATENTAtty. Dkt. No. 70910-02 identified by TEM in various experiemtnation. The cross-sectional TEM image and EDX mapping revealed that the SnOx interphase, with a thickness of approximately 70 nm, is uniformly coated on the Zn foil.

[0048] Ultra Thin Thickness. The XRD results of pristine Zn and the SnOx interphase- modified Zn anode were analyzed according to various experimentation. Distinguished peaks were found at 36.3°, 38.9°, 43.2°, 54.3°, 70.1 °, and 70.6°, which are attributed to the metallic Zn, are observed in pristine Zn and the SnOx interphase-modified Zn anode. In addition, weak peaks located at 18.1 ° and 33.4° in the SnOx interphase-modified Zn anode are attributed to polycrystalline SnO phases.

[0049] XRD Results. The laser confocal microscope images of the pristine Zn and the SnOx interphase-modified Zn anode after Zn plating were analyzed according to various experimntation. The high surface roughness (arithmetic mean height, Sa) of 10.02 pm in pristine Zn suggests an uneven Zn2+ plating process, which was ascribed to the formation of Zn dendrites. In contrast, the SnOx interphase-modified Zn anode exhibits a Sa of 5.52 pm, indicating the uniform Zn2+ plating process.

[0050] Zn plating underlying the configured interphase for water separation. I n various experimentation, the Zn ions plating location was guided underlying the SnOx interphase. The EDX result of the electrode after Zn plating shows the distinct Sn information at a range of 3-5 keV. Moreover, peaks located at 18.1 and 33.4o in XRD results can be assigned to the SnO, which further validates the Zn ions were plated underlying the SnOx interphase.

[0051] High ionic conductivity and electron blocking for underlying Zn plating. The underlying plating behavior was governed by the synergetic effects of the high ionic conductivity and the built-in electrostatic interactions of the SnOx interphase. By controlling the Sn / O ratio and the annealing time, the SnOx exhibits an ionic conductivity of 1 .36 x 10-4 mS cm-1 .

[0052] Selective / preferred growth of Zn orientation (101). The underlying plated Zn was well-aligned with the orientation of Zn (101 ) at different cycling times as indicated by XRD results. The diffraction peak of Zn (101 ) shows much higher intensity compared toPATENTAtty. Dkt. No. 70910-02 peaks of other orientations, indicating the preferential growth of Zn (101 ) in the entire battery cycling.

[0053] Lowering surface energy ofZn (101) for the selective growth. The preferential growth of Zn (101 ) was achieved by decreasing the surface energy of Zn (101 ). The surface energy of Zn (101 ) decreased from 1.65 to 0.74 eV after applying the SnOx interphase.

[0054] Enhancement by the SnOx interphase. The SnOx interphase-modified Zn anode delivered higher cycling stability and lower overpotential compared to the pristine Zn anode and Zn anode modified by the traditional artificial interphase under 1 mA cm-2 and 20 mA cm-2.

[0055] Enhancement by the SnOx interphase. The SnOx interphase-modified Zn anode shows higher capacity retention of 95.2% compared to the 66.9% of the pristine Zn anode and the 77.4% of the anode modified by traditional artificial interphase when paired with the PEDOT-coated sulfur cathode (PEDOT@S) in the full battery.

[0056] Enhancement by the SnOx interphase. The SnOx interphase-modified thin Zn anode (~2.6 urn) shows higher capacity retention of 90.5% compared to the 26.4% of the anode modified by traditional artificial interphase when paired with the MnO2 cathode in the full battery.

[0057] Zn free anode system application. The SnOx interphase can be generalized to other metal anodes (e.g., Cu). The SnOx interphase-modified Cu anode exhibits higher capacity retention of 87.6% compared to the 30.9% of the anode modified by traditional artificial interphase when paired with the ZnMn2O4 cathode in an Zn free system .

[0058] A second action may be said to be "in response to" a first action independent of whether the second action results directly or indirectly from the first action. The second action may occur at a substantially later time than the first action and still be in response to the first action. Similarly, the second action may be said to be in response to the first action even if intervening actions take place between the first action and the second action, and even if one or more of the intervening actions directly cause the second action to be performed. For example, a second action may be in response to a first action if thePATENTAtty Dkt. No. 70910-02 first action sets a flag and a third action later initiates the second action whenever the flag is set.

[0059] To clarify the use of and to hereby provide notice to the public, the phrases "at least one of , , ... and <N>" or "at least one of , , ... <N>, or combinations thereof" or ", , ... and / or <N>" are defined by the Applicant in the broadest sense, superseding any other implied definitions hereinbefore or hereinafter unless expressly asserted by the Applicant to the contrary, to mean one or more elements selected from the group comprising A, B, ... and N. In other words, the phrases mean any combination of one or more of the elements A, B, ... or N including any one element alone or the one element in combination with one or more of the other elements which may also include, in combination, additional elements not listed.

[0060] While various embodiments have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible. Accordingly, the embodiments described herein are examples, not the only possible embodiments and implementations.

Claims

PATENTAtty. Dkt. No. 70910-02CLAIMSWhat is claimed is:1 . 1 . An anode for aqueous zinc-ion battery comprising: an electrode; and an interphase layer disposed on the electrode, the interphase layer comprising a non-stoichiometric tin oxide (SnOx) where 1 < x <= 1 .2, wherein the interphase layer guides Zn2+ions to plate beneath the interphase layer along the Zn (101 ) crystallographic orientation.

2. The anode of claim 1 , wherein the interphase layer has a thickness between about 50 nm and 100 nm.

3. The anode of claim 1 , wherein the interphase layer is formed by magnetron sputtering of a tin target in an oxygen / argon atmosphere, followed by annealing.

4. The anode of claim 1 , wherein the interphase layer is hydrophobic and isolates the electrode from water in an electrolyte.

5. The anode of claim 1 , wherein the interphase layer comprises dative bonds at the interface with the electrode, saturating dangling bonds of the Zn (101 ) facet.

6. The anode of claim 1 , wherein the electrode comprises a zinc substrate.

7. A method of manufacturing a aqueous zinc ion battery, comprising: providing an electrode; depositing a thin layer of tin oxide (SnOx) onto the electrode by magnetron sputtering where x is greater than 1 .0 and less than or equal to 1 .2;PATENTAtty. Dkt. No. 70910-02 annealing the tin oxide-coated electrode for a duration sufficient to induce crystallization of the SnOx interphase; assembling the treated electrode into an electrochemical cell comprising an electrolyte; and forming a compact, highly oriented zinc plating with a predominant (101 ) crystal orientation beneath the interphase layer.

8. The method of claim 7, wherein the electrode comprises a zinc substrate.

9. The method of claim 7, further comprising polishing the electrode to remove native oxide and expose a clean metallic surface.

10. The method of claim 7, wherein the interface layer has a thickness between about 50 nm and 100 nm.1 1 . The method of claim 7, wherein the underlying zinc plating is isolated from direct contact with the electrolyte by the SnOx interphase, thereby suppressing water-induced corrosion and hydrogen evolution reactions.

12. The method of claim 7, wherein the interphase layer is deposited by magnetron sputtering using a tin target and a reactive sputter gas comprising oxygen and argon.

13. The method of claim 12, wherein the oxygen-to-argon ratio in the sputter gas is adjusted to tune the stoichiometry of the tin oxide.

14. An electrochemical cell comprising: an anode disposed in a zinc-based aqueous electrolyte, the anode comprising: an interphase layer disposed on the electrode, the interphase layer comprising a non-stoichiometric tin oxide (SnOx) where 1 < x <= 1 .2,PATENTAtty. Dkt. No. 70910-02 wherein the interphase layer guides Zn2+ions to plate beneath the interphase layer along the Zn (101 ) crystallographic orientation.

15. The electrochemical cell of claim 14, wherein the interphase layer has a thickness between about 50 nm and 100 nm.

16. The electrochemical cell of claim 14, wherein the interphase layer is formed by magnetron sputtering of a tin target in an oxygen / argon atmosphere, followed by annealing.

17. The electrochemical cell of claim 14, wherein the interphase layer is hydrophobic and isolates the electrode from water in an electrolyte.

18. The electrochemical cell of claim 14, wherein the interphase layer comprises dative bonds at the interface with the electrode, saturating dangling bonds of the Zn (101 ) facet.

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