Composite cathode containing coated carbon fibers and all-solid-state battery containing the same

Abstract

A cathode composite layer for an all-solid-state battery is disclosed, said composite layer comprises particles of a cathode active material (CAM), a solid electrolyte (SE), and electrically conductive carbon fibers coated with an oxide material. In one embodiment, the present disclosure provides an all-solid-state battery comprising a cathode composite layer, said battery having reduced SE degradation and increased capacity and cycle stability.

Description

Technology Field

[0001] (Cross-reference)

[0002] This application claims the benefit of U.S. Patent Application No. 63 / 389,383 filed July 15, 2022 and U.S. Patent Application No. 63 / 350,665 filed June 9, 2022, the entire contents of each of which are incorporated herein by reference in their entirety.

[0003] (Technology field)

[0004] The present disclosure relates to a cathode layer or a cathode composite layer for an all-solid-state battery. Background Technology

[0005] All-solid-state batteries (ASSBs) are considered promising candidates for future energy storage devices because they can utilize lithium metal as an anode material and deliver higher specific energy compared to conventional lithium-ion batteries based on organic liquid electrolytes. Thiophosphate-based solid electrolytes (SEs) appear particularly promising due to their high ionic conductivity, excellent mechanical compatibility, and relatively low cost. Generally, however, the low thermodynamic stability of SEs, as well as issues regarding chemical-mechanical coupling and interfacial reaction kinetics, remain major challenges. In cathode complexes, side reactions include a) decomposition occurring at the current collector / SE interface at high potentials, b) the formation of a resistive interfacial layer due to reactions between the cathode active material (CAM) and the SE, and c) decomposition reactions occurring at the carbon / SE interface when carbon conductive additives are used. Excessive degradation of the SE is due to the Li in the cathode layer + Mobility decreases, and capacity decreases over time.

[0006] Composite cathodes composed of carbon fibers (CF), such as vapor-grown carbon fibers (VGCF), exhibit higher initial capacity compared to corresponding ASSBs without CF because more CAM particles are electronically linked, resulting in higher CAM utilization. However, this initial capacity is not sustained, and a rapid decline in capacity is observed during cell cycling as the SE degradation rate (at both the CAM / SE and carbon / SE interfaces) increases. For example, LPS (Li7P3S 11 In the case of the electrolyte, when the potential exceeds 2.1V and moves out of the potential stability window of the SE, the sulfide SE deteriorates at the CAM / SE and / or CF / SE interface.

[0007] In order to minimize the effects of SE degradation, it is very important to reduce SE degradation in the cathode composite layer, especially in those with a high CAM ratio, for example, 86 wt% or more, and those with a low SE ratio, for example, 14 wt% or less.

[0008] US Patent No. 7150911 B2 describes vapor-grown carbon fibers (VGCF) coated with an electrical insulating material, such as boron nitride, as a thermally conductive and electrically insulating filler. However, the resistivity of the coated VGCF disclosed in this document is 10 x 10 3 Since it is greater than Ω·cm, it can block the electrical connection path required for the electrode layer.

[0009] US 20150228966 A1 discloses an all-solid-state battery using carbon fiber as a conductive material in the CAM layer to improve initial capacity by increasing the utilization of the CAM by increasing the electronic conduction path. US 9219271 B2 discloses an all-solid-state battery using a conductive carbon additive in the cathode layer. However, neither of these discloses coated carbon materials. The SE degradation problem still remains. means of solving the problem

[0010] In one embodiment, the present disclosure relates to particles of a cathode active material (CAM), a sulfide solid electrolyte, and an oxide material (e.g., Li3B). 11 O 18 A cathode layer comprising carbon fibers (CF) coated with ) is provided, wherein particles of the cathode active material (CAM) are electronically contacted with the carbon fibers (CF) by pressure, for example, during manufacturing. In one embodiment, the present disclosure provides an all-solid-state battery comprising a cathode layer. In one embodiment, the ASSB has reduced solid electrolyte (SE) degradation at the VGCF / SE interface, thereby improving capacity and cycle stability. Brief explanation of the drawing

[0011] Fig. 1 A representative structure of an ASSB having a cathode layer composed of a CAM particle (1) coated with a silver oxide material (4), a sulfide SE (2), and a VGCF (3), wherein the CAM particle is in electronic contact with the VGCF. Fig. 2 Is Li3B with a thickness of approximately 1-2 nm 11 O 18 Shows a TEM (transmission electron microscope) image of carbon fiber coated with a (LBO) layer. Fig. 3 silver NCA88 (LiNi as Li metal anode, LPS SE, and CAM) 0.88 Co 0.09 Al 0.03 This shows a specific capacity versus cycle plot of a half-cell composed of a cathode layer containing O2 particles and VGCF (uncoated or coated). Cycles 1 and 2 are performed with 0.1C charge / discharge; cycles 3 and 4 are performed with 0.33C charge / discharge; cycle 5 is performed with 1.0C charge / discharge; and cycles 6–25 are performed with 0.5C charge / discharge at 45 °C. The cycle plot compares the uncoated VGCF with 2, 20, 50, and 100 nm LBO-coated VGCF. Fig. 4 Is Li metal anode, LPS as SE, NCA88 (LiNi 0.88 Co 0.09 Al 0.03 This shows the specific capacity versus cycle plot of half-cells composed of O2 particles and VGCF (uncoated or coated). Cycles 1 and 2 are performed with 0.1C charge / discharge; cycles 3 and 4 are performed with 0.33C charge / discharge; cycle 5 is performed with 1.0C charge / discharge; and cycles 6–25 are performed with 0.5C charge / discharge. The cycle plot shows uncoated VGCF with 20nm B2O3, LBO (Li3B 11 O 18 Compare with ), Li3BO3, and 10nm LiNbO3. Specific details for implementing the invention

[0012] In one embodiment, the present disclosure provides a cathode composite layer comprising particles of a cathode active material (CAM) (1), a sulfide-based solid electrolyte (2), and carbon fibers (3) coated with an oxide material (4). In one embodiment, a representative structure is shown in FIG. 1.

[0013] In one embodiment, the sulfide solid electrolyte used in the present disclosure may be any sulfide solid electrolyte as long as it contains Li and S and has the desired lithium ion conductivity. The sulfide solid electrolyte may be one of a crystalline material, glass ceramic, and glass. Examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-P2S5-LiHa ("Ha" is one or more halogen elements), Li2S-P2S5-P2O5, Li2S-Li3PO4-P2S5, Li3PS4, Li4P2S6, Li 10 GeP2S 12 , Li 3.25 Ge 0.25 P 0.75 S4, Li7P3S 11 , Li 3.25 P 0.95 S4, and Li7-x PS 6-x Ha x Examples include an azyrodite-type solid electrolyte, where "Ha" is one or more halogen elements, and 0.2 < x < 1.8. The concentration of the cathode layer is 1 wt% to 30 wt%.

[0014] In one embodiment, electrically conductive carbon fibers include, without limitation, vapor-grown carbon fibers (VGCF), carbon nanotubes (CNT), multi-walled carbon nanotubes (MWCNT), carbon nanofibers, and graphite fibers. The CF is 1–600 m 2 It has a BET measured specific surface area between / g and an electrical resistance of 0.5 Ω·cm or less. In one embodiment, the fiber has a concentration of 0.01 wt% to 5 wt% in the cathode layer.

[0015] In one embodiment, the oxide material is an electrical insulating material. In one embodiment, the oxide material is an inorganic oxide material. In one embodiment, the oxide material contains Li, a second element, and a third element. In one embodiment, the second element is one or more elements from Groups 15 and 16 of the periodic table, e.g., O, N, S, P. In one embodiment, the third element is a transition metal or one or more elements from Groups 13 and 14 of the periodic table, e.g., B, C, Al, Si, Ga, and Ge. In one embodiment, the oxide material is an oxide containing Li, B, and one or more elements selected from the group consisting of, e.g., B, Nb, Ti, Zr, Ta, Zn, W, and Al. In one embodiment, the oxide material is lithium borate, alumina, lithium zirconate (Li2ZrO3), LiNbO3, Li4SiO4, Li3PO4, Li2SiO3, LiPO3, Li2SO4, Li2WO4, Li2MoO4, LiAlO2, Li2TiO3, Li4Ti5O 12..., or is an inorganic oxide material including, but not limited to, composite oxides thereof. In one embodiment, lithium borate is Li3B without limitation. 11 O 18 , Li3BO3, Li4B2O5, Li6B4O9, LiBO2, Li2B4O7, Li3B7O 12 ...and includes LiB3O5. In one embodiment, the inorganic oxide is another material having a wide potential stability window, for example, from 1.9 V to 5.0 V. For example, the inorganic oxide material has a stable potential window of at least 1.5 V with respect to Li / Li+. In one embodiment, the inorganic oxide material has a stable potential window of at least 2.0 V with respect to Li / Li+. In one embodiment, the inorganic oxide material is Li / Li + It has a stable potential window of at least 2.5 V based on . In one embodiment, the inorganic oxide material is Li / Li + It has a stable potential window of at least 3.0 V based on . In one embodiment, the inorganic oxide material is Li / Li + It has a stable potential window of at least 4.0 V based on . In one embodiment, the inorganic oxide material is Li / Li + It has a stable potential window of at least 4.5 V based on . In one embodiment, the inorganic oxide material is Li / Li + It has a stable potential window of at least 5.1 V based on .

[0016] In one embodiment, the cathode composite layer is sandwiched between the cathode current collector and the solid electrolyte layer. In one embodiment, the cathode composite layer is sandwiched between the SE layer and the current collector and lithium ions (Li + It includes cathode active materials (CAM) that require both ) and electron (e-) connectivity. Li +Connectivity is primarily provided by small particles of sulfide-based SE within the cathode complex mixture, while e-connectivity is primarily provided by CF. Sulfide-based SEs (e.g., LPS) possess high Li+ conductivity. However, they generally exhibit Li / Li at CAM / SE, CF / SE, and collector / SE interfaces. + Compared to that, performance degrades at potentials below 1.7 V or above 2.1 V. Degraded byproducts generally have lower Li+ conductivity, which leads to a higher SE ratio in the cathode composite layer and a lower CAM ratio. Consequently, degradation narrows the battery operating voltage window and inhibits the ability to produce high energy density batteries.

[0017] In one embodiment, the present disclosure discloses a carbon fiber coated with an oxide material layer or coating for a cathode composite layer. In one embodiment, the coating is Li3B having a wide voltage stability range of 1.9–4.7 V compared to Li / Li+. 11 O 18The present disclosure has found that the thickness of the oxide material layer is very important. A thick coating can completely block the electron conduction pathway, which is essential for the operation of all solid-state batteries. A thin coating may make no difference compared to uncoated carbon fiber and does not help reduce degradation. Meanwhile, the coating has a constant thickness to provide constant electrical insulation, thereby reducing SE degradation at the CF / SE interface. In one embodiment, the thickness is 1 nm or more. In one embodiment, the thickness is 2 nm or more. In one embodiment, the thickness is 5 nm or more. In one embodiment, the thickness is 10 nm or more. In one embodiment, the minimum thickness depends on several factors such as the coating composition, intrinsic properties, and the coating-CF interface. On the other hand, the coating must not be too thick and must be thin enough to be penetrated by hard CAM particles during battery formation (5000 lbs / in 2(Press), thereby providing electrical contact between the CAM particles and the VGCF. In one embodiment, the thickness does not exceed 200 nm. In one embodiment, the thickness does not exceed 150 nm. In one embodiment, the thickness does not exceed 100 nm. In one embodiment, the thickness does not exceed 80 nm. In one embodiment, the thickness does not exceed 50 nm. In one embodiment, the thickness does not exceed 30 nm. In one embodiment, the maximum thickness depends on several factors such as the coating composition, intrinsic properties, and the coating-CF interface. In one embodiment, the cathode composite layer as disclosed in this disclosure significantly reduces SE degradation, thereby achieving a high initial specific capacity close to 100% CAM utilization while improving cycle life stability. In one embodiment, the coating has a thickness of 1-5 nm. In one embodiment, the coating has a thickness of 1-20 nm. In one embodiment, the coating has a thickness of 1-50 nm. In one embodiment, the coating has a thickness of 1-80 nm. In one embodiment, the coating has a thickness of 1-100 nm. The present disclosure will be better understood by referring to the following experimental details, but those skilled in the art will readily understand that the specific experimental details described above are merely for illustrative purposes and are not intended to limit the disclosure described herein, as defined by the following claims.

[0018] In one embodiment, oxide materials can transport lithium ions in a cathode composite layer. Without being bound by any theory, lithium ion conductivity is attributed to defects in the crystal structure of inorganic oxides and the relatively small activation energy required for the ion transport process. Islam, M. et al 2012 J. Phys.:Condens.Matter 24 203201.

[0019] In one embodiment, the present disclosure provides a composite layer as a cathode for an all-solid-state battery, wherein the composite layer comprises particles of a cathode active material (CAM), a solid electrolyte, and carbon fibers coated with an oxide material. In one embodiment, the oxide material is an electrical insulating material.

[0020] In one embodiment, the oxide material coated on the carbon fiber has a thickness of 1-80 nm.

[0021] In one embodiment, the oxide material coated on the carbon fiber has a thickness of 2-50 nm. In some embodiments, the oxide material coated on the carbon fiber is 1 nm to 100 nm, 1 nm to 90 nm, 1 nm to 80 nm, 1 nm to 70 nm, 1 nm to 60 nm, 1 nm to 50 nm, 1 nm to 40 nm, 1 nm to 30 nm, 1 nm to 25 nm, 1 nm to 20 nm, 1 nm to 15 nm, 1 nm to 10 nm, 2 nm to 100 nm, 2 nm to 90 nm, 2 nm to 80 nm, 2 nm to 70 nm, 2 nm to 60 nm, 2 nm to 50 nm, 2 nm to 40 nm, 2 nm to 30 nm, 2 nm to 25 nm, 2 nm to 20 nm, 2 nm to 15 nm, 2 nm to 10 nm, 5 nm to 100 nm, 5 nm to It has a thickness of 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, 5 nm to 25 nm, 5 nm to 20 nm, 5 nm to 15 nm, 5 nm to 10 nm, 10 nm to 100 nm, 10 nm to 90 nm, 10 nm to 80 nm, 10 nm to 70 nm, 10 nm to 60 nm, 10 nm to 50 nm, 10 nm to 40 nm, 10 nm to 30 nm, 10 nm to 25 nm, 10 nm to 20 nm, 10 nm to 15 nm, or all in between and sub-ranges. In some embodiments, thickness is measured by observing the cross-section of the dissected particle using a scanning electron microscope (SEM). In some embodiments, thickness is measured using a transmission electron microscope (TEM).

[0022] In one embodiment, CAM particles have a weight percentage of at least 65% in the composite layer.

[0023] In one embodiment, carbon fibers coated with an oxide material have a weight percentage of 0.01 to 5.0 weight percent in the composite layer.

[0024] In one embodiment, carbon fibers coated with an oxide material have a weight percentage of 1.0 weight% to 3.0 weight% in the composite layer.

[0025] In one embodiment, the oxide material is an inorganic oxide material with a wide voltage stability window.

[0026] In one embodiment, the inorganic oxide material is B2O3, Li3B 11 O 18 , Li3BO3, Li4B2O5, Li6B4O9, LiBO2, Li2B4O7, Li3B7O 12 , LiB3O5, LiNbO3, Li4SiO4, Li3PO4, Li2SiO3, LiPO3, Li2SO4, Li2WO4, Li2MoO4, Li2ZrO3, LiAlO2, Li2TiO3, Li4Ti5O 12 , or is selected from the group consisting of complex oxides thereof.

[0027] In one embodiment, the inorganic oxide material is stable in a voltage range from 1.9 V to 5.0 V.

[0028] In some embodiments, the inorganic oxide material is Li2CO3 (LCBO) doped with Li3BO3, where the ratio of Li2CO3 to Li3BO3 is Li 2+x C 1-x B xO3으로 표현된다. 일부 양태에서, 0 < x < 1, 0 < x ≤ 0.9, 0 < x ≤ 0.80, 0 < x ≤ 0.70, 0 < x ≤ 0.60, 0 < x ≤ 0.50, 0 < x ≤ 0.45, 0 < x ≤ 0.40, 0 < x ≤ 0.35, 0 < x ≤ 0.30, 0 < x ≤ 0.25, 0 < x ≤ 0.20, 0 < x ≤ 0.15, 0 < x ≤ 0.10, 0.10 ≤ x < 1, 0.10 ≤ x ≤ 0.90, 0.10 ≤ x ≤ 0.80, 0.10 ≤ x ≤ 0.70, 0.10 ≤ x ≤ 0.60, 0.10 ≤ x ≤ 0.50, 0.10 ≤ x ≤ 0.45, 0.10 ≤ x ≤ 0.40, 0.10 ≤ x ≤ 0.35, 0.10 ≤ x ≤ 0.30, 0.10 ≤ x ≤ 0.25, 0.10 ≤ x ≤ 0.20, 0.15 ≤ x < 1, 0.15 ≤ x ≤ 0.90, 0.15 ≤ x ≤ 0.80, 0.15 ≤ x ≤ 0.70, 0.15 ≤ x ≤ 0.60, 0.15 ≤ x ≤ 0.50, 0.15 ≤ x ≤ 0.45, 0.15 ≤ x ≤ 0.40, 0.15 ≤ x ≤ 0.35, 0.15 ≤ x ≤ 0.30, 0.15 ≤ x ≤ 0.25, 0.20 ≤ x < 1, 0.20 ≤ x ≤ 0.90, 0.20 ≤ x ≤ 0.80, 0.20 ≤ x ≤ 0.70, 0.20 ≤ x ≤ 0.60, 0.20 ≤ x ≤ 0.50, 0.20 ≤ x ≤ 0.45, 0.20 ≤ x ≤ 0.40, 0.20 ≤ x ≤ 0.35, 0.20 ≤ x ≤ 0.30, 0.25 ≤ x < 1, 0.25 ≤ x ≤ 0.90, 0.25 ≤ x ≤ 0.80, 0.25 ≤ x ≤ 0.70, 0.25 ≤ x ≤ 0.60, 0.25 ≤ x ≤ 0.50, 0.25 ≤ x ≤ 0.45, 0.25 ≤ x ≤ 0.40, 0.25 ≤ x ≤ 0.35, 0.30 ≤ x < 1, 0.30 ≤ x ≤ 0.90, 0.30 ≤ x ≤ 0.80, 0.30 ≤ x ≤ 0.70, 0.30 ≤ x ≤ 0.60, 0.30 ≤ x ≤ 0.50, 0.30 ≤ x ≤ 0.45, 0.30 ≤ x ≤ 0.40, 0.35 ≤ x < 1, 0.35 ≤ x ≤ 0.90, 0.35 < 0.60, 0.35 ≤ x ≤ 0.50, 0.35 ≤ x ≤ 0.45, 0.40 ≤ x < 1, 0.40 ≤ x ≤ 0.90, 0.40 ≤ x ≤ 0.80, 0.40 ≤ x ≤ 0.70, 0.40 ≤ x ≤ 0.60, 0.40 ≤ x ≤ 0.50, 0.45 ≤ x < 1, 0.45 ≤ x ≤ 0.90, 0.45 ≤ x ≤ 0.80, 0.45 ≤ x ≤ 0.70, 0.45 ≤ x ≤ 0.60, 0.50 ≤ x < 1, 0.50 ≤ x ≤ 0.90, 0.50 ≤ x ≤ 0.80, 0.50 ≤ x ≤ 0.70, 0.50 ≤ x ≤ 0.60, 0.70 ≤ x < 1, 0.70 ≤ x ≤ 0.90, 0.70 ≤ x ≤ 0.80, and all ranges and sub-ranges in between.

[0029] In one embodiment, the solid electrolyte is an inorganic electrolyte containing sulfur.

[0030] In one embodiment, the solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiHa, Li2S-P2S5-P2O5, Li2S-Li3PO4-P2S5, Li3PS4, Li4P2S6, Li 10 GeP2S 12 , Li 3.25 Ge 0.25 P 0.75 S4, Li7P3S 11 , Li 3.25 P 0.95 S4, and Li 7-x PS 6-x Ha x It is selected from the group consisting of, where "Ha" is one or more halogen elements, and 0.2 < x < 1.8.

[0031] In one embodiment, the solid electrolyte has a weight percentage of 1% to 35% by weight in the composite layer. In some embodiments, the solid electrolyte may have a concentration in the composite layer of 1 wt% to 35 wt%, 1 wt% to 30 wt%, 1 wt% to 25 wt%, 1 wt% to 20 wt%, 1 wt% to 15 wt%, 1 wt% to 10 wt%, 5 wt% to 35 wt%, 5 wt% to 30 wt%, 5 wt% to 25 wt%, 5 wt% to 20 wt%, 5 wt% to 15 wt%, 10 wt% to 35 wt%, 10 wt% to 30 wt%, 10 wt% to 25 wt%, 10 wt% to 20 wt%, 15 wt% to 35 wt%, 15 wt% to 30 wt%, 15 wt% to 25 wt%, 20 wt% to 30 wt%, or any range and sub-range in between.

[0032] In one embodiment, CAM is Li x Mn 1-y M y A2, Li x Mn 1-y M y O 2-z X z , Li x Mn2O 4-z X z , Li x Mn 2-y M y A4, Li x Co 1-y M y A2, Li x Co 1-y M y O 2-z X z , Li x Ni 1-y M y A2, Li x Ni 1-y M y O 2-z X z , Li x Ni 1-y Co y O2-z X z , Li x Ni 1-y-z Co y M z A a , Li x Ni 1-y-z Co y M z O 2-a X a , Li x Ni 1-y-z Mn y M z A a , Li x Ni 1-y-z Mn y M z O 2-a X a It is selected from the group consisting of , wherein 0.95 ≤ x ≤ 1.1, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.5, 0 ≤ a ≤ 2; M is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V and rare earth elements; A is selected from the group consisting of O, F, S and P; and X is selected from the group consisting of F, S and P.

[0033] In some embodiments, CAM is Li x MO2, Li x Ni 1-y-z Co y M1 z O2 and Li x Ni 1-y-z Mn y M2 zOne or more selected from the group consisting of O2, where M is one or more selected from the group consisting of Ni, Co, Mn, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn and rare earth elements, where M1 is one or more selected from the group consisting of Mn, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn and rare earth elements, where M2 is one or more selected from the group consisting of Co, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn and rare earth elements, where 0.95 ≤ x ≤ 1.1, 1-yz>0, 0< y ≤ 0.5, 0 ≤ z ≤ 0.5.

[0034] In some embodiments, CAM is Li x MO2, Li x Ni 1-y-z Co y M1 z O2 and Li x Ni 1-y-z Mn y M2 zAt least one selected from the group consisting of O2, where M is one or more selected from the group consisting of Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, and rare earth elements, where M1 is one or more selected from the group consisting of Mn, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, and rare earth elements, where M2 is one or more selected from the group consisting of Co, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, and rare earth elements, where 0.95 ≤ x ≤ 1.1, 1-yz>0, 0< y ≤ 0.5, 0 ≤ z ≤ 0.5.

[0035] In some embodiments, the CAM is surface-doped with at least one doping element selected from the group consisting of Ni, Co, Mn, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, Si, Ge, S, P and rare earth elements.

[0036] In some embodiments, the CAM is in the form of particles having an average diameter within the range of about 1 μm to about 15 μm, about 1 μm to about 12 μm, about 1 μm to about 10 μm, about 1 μm to about 7 μm, about 1 μm to about 6 μm, about 3 μm to about 15 μm, about 3 μm to about 12 μm, about 3 μm to about 10 μm, about 3 μm to about 7 μm, about 3 μm to about 6 μm, about 5 μm to about 15 μm, about 5 μm to about 12 μm, about 5 μm to about 10 μm, and all in between and sub-ranges. In some embodiments, the coated CAM in the cathode layer is about 50 wt% to about 99 wt%, about 50 wt% to about 95 wt%, about 50 wt% to about 90 wt%, about 50 wt% to about 85 wt%, about 50 wt% to about 80 wt%, about 55 wt% to about 99 wt%, about 55 wt% to about 95 wt%, about 55 wt% to about 90 wt%, about 55 wt% to about 85 wt%, about 55 wt% to about 80 wt%, about 60 wt% to about 99 wt%, about 60 wt% to about 95 wt%, about 60 wt% to about 90 wt%, about 60 wt% to about 85 wt%, about 60 wt% to about 85 wt%, about 60 wt% to about 80 wt%, about 65 wt% to about 99 wt%, about 65 wt% to It may have concentrations of about 95 wt%, about 65 wt% to about 90 wt%, about 65 wt% to about 85 wt%, about 65 wt% to about 80 wt%, about 70 wt% to about 99 wt%, about 70 wt% to about 95 wt%, about 70 wt% to about 90 wt%, about 70 wt% to about 85 wt%, about 70 wt% to about 80 wt%, and all ranges and sub-ranges in between. In some embodiments, the CAM particles may be polycrystalline or single-crystal.In some embodiments, CAM particles may have a single particle size distribution or a multiple particle size distribution.

[0037] In some embodiments, CAM contains the element Ni, in which the mole fraction of all metal elements excluding lithium is at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, or at least 85%.

[0038] In one embodiment, the particle has an average diameter of 1-15 μm.

[0039] In one embodiment, the present disclosure provides an all-solid-state battery (ASSB) comprising the following:

[0040] a) a composite layer as an anode, and

[0041] b) A solid electrolyte layer between the anode and the cathode.

[0042] In one embodiment, the solid electrolyte layer is composed of a second solid electrolyte, which is the same as or different from the solid electrolyte of the cathode composite layer.

[0043] In one embodiment, the composite layer comprises at least 65 weight percent of CAM particles.

[0044] In one embodiment, the ASSB has an initial discharge specific capacity of at least 180 mAh / g at a discharge rate of 0.5C.

[0045] In one embodiment, the ASSB has an initial discharge capacity of at least 200 mAh / g at a discharge rate of 0.1C.

[0046] In one embodiment, after 20 cycles at a discharge rate of 0.5C, the ASSB has a specific capacity of at least 180 mAh / g and a capacity retention rate of at least 95%.

[0047] The present disclosure will be better understood by referring to the following experimental details, but those skilled in the art will readily understand that the specific experimental details described above are for illustrative purposes only and are not intended to limit the disclosure described herein, as defined by the following claims.

[0048] The transitional term "comprising," which is synonymous with "including," "containing," or "characterized by," is inclusive or open and does not exclude additional unmentioned elements or method steps.

[0049] Example 1

[0050] Carbon fibers coated with oxide materials were prepared using the traditional sol-gel method. Li3B 11 O 18 For coating, stoichiometric amounts of a Li precursor (e.g., lithium acetate or lithium metal) and a B precursor (e.g., triisopropyl borate) were dissolved in a dry solvent (e.g., ethanol) to form a coating solution containing the lithium precursor and the borate precursor. The coating solution was then coated with a predetermined amount of CF (VGCF-H, fiber diameter 150 nm, fiber length 10–20 μm, BET surface area 13 m²). 2 / g, aspect ratio 10 - 500, true density 2.0 g / cm³ 3 , Apparent density VGCF(R) (Standard type) 0.04 g / cm³, Short fiber resistivity 1 x 10⁻⁶ -4 It was added to (Ωcm). A predetermined amount of CF was added to the CF BET surface area and bulk density (Li3B) on the coating. 11 O 18 In the case of 2.16 g / cm³ 3It is calculated to provide the desired coating thickness based on ). After stirring the mixture for 30 minutes, the solvent is removed via vacuum while sonicating to produce a CF gel coated with Li precursors and B precursors. Subsequently, the CF gel is annealed at 300 °C under an oxygen flow for 1 hour to produce Li3B 11 O 18 Forms layered carbon fibers. Specific discharge capacity and cycle life retention rate of various cathode layers, including coated CF and uncoated CF. Table 1 It is summarized in ). The cathode layer consists of 65 wt% CAM (NCA88), 5 wt% CF (coated or uncoated), and 30 wt% LPS. The cathode layer is electrochemically evaluated in a torque cell using Li metal placed on copper as the anode and LPS as the SE. The cell was cycled at 2.8 V to 4.25 V with 0.1 C charge / discharge in cycles 1 and 2, at 0.33 C charge / discharge in cycles 3 and 4, at 1.0 C charge / discharge in cycle 5, and at 0.5 C charge / discharge at 45 °C in cycles 6 to 25.

[0051] To achieve a high initial discharge capacity, carbon fibers or other electronically conductive materials are required to electronically connect all CAM particles in the cathode layer. However, significant fading occurs due to the decomposition of the SE in contact with the CF. In this disclosure, this is addressed by an oxide material with a thickness of 2–50 nm on the CF (e.g., LBO (Li3B)). 11 O 18 It was resolved by ). The coating thickness is stoichiometrically calculated using the BET surface area of ​​CF, the bulk density of the coating composition, and the mass / molar of the reagent in the coating solution (assuming reagent utilization is 100%). The coating thickness is confirmed through TEM analysis. Representative TEM images Fig. 2 It is built in.

[0052] Coated CF reduced the fading of discharge capacity while maintaining a high level of initial battery performance. For example, for a half-battery composed of uncoated VGCF, the initial discharge capacity at a discharge rate of 0.1C is 205.33 mAh / g. When LBO is coated on VGCF at 2, 20, and 50 nm, the initial discharge capacities are 203.91 mAh / g, 206.76 mAh / g, and 219.23 mAh / g, respectively. When the thickness of LBO is 100 nm, the initial discharge capacity decreases to 178.73 mAh / g. Table 1 class Fig. 3 As clearly demonstrated by the cycle life capacity retention rate after 20 cycles at 0.5C, the coated CF effectively reduces cell degradation, and furthermore, the initial discharge capacity at a rate of 0.1C is the theoretical capacity of CAM (NCA88 -- LiNi 0.88 Co 0.09 Al 0.03 As it has been proven that the initial discharge capacity increases at a rate of 0.1C approaching 219.8 mAh / g in the case of O2, this may be important for realizing high-capacity SSB.

[0053] [Table 1] Initial discharge (dChg.) capacity (Cap.) at various C-rates using uncoated VGCF and LBO-coated VGCF with different coating thicknesses

[0054]

[0055] a: Cycle life 0.5C dChg. capacity retention rate is calculated by dividing the 20th cycle 0.5C dChg. capacity by the initial 0.5C dChg. capacity and multiplying by 100%.

[0056] VGCF coatings are not limited to lithium-containing oxides or lithium borates. Fig. 4 is 20nm B2O3, 20nm Li3B 11 O 18This shows the cycling performance of uncoated VGCF containing 20 nm Li3BO3 and 10 nm LiNbO3. The cathode layer consists of 65 wt% CAM (NCA88), 5 wt% CF (coated or uncoated), and 30 wt% LPS. The cathode layer is electrochemically evaluated in a torque cell using Li metal placed on copper as the anode and LPS as the SE. The cell was cycled at 2.8 V to 4.25 V with 0.1 C charge / discharge in cycles 1 and 2, 0.33 C charge / discharge in cycles 3 and 4, 1.0 C charge / discharge in cycle 5, and 0.5 C charge / discharge in cycles 6 through 25. All coating compositions, except for Li3BO3, showed improved discharge capacity and capacity retention at the 25th cycle compared to the uncoated VGCF.

[0057] [Table 2] Uncoated VGCF and 20nm B2O3, Li3B 11 O 18 Initial discharge (dChg.) capacity (Cap.) at various C-rates of half-cells using Li3BO3 and 10 nm LiNbO3-coated VGCF.

[0058]

[0059] a: Cycle life 0.5C dChg. capacity retention rate is calculated by dividing the 20th cycle 0.5C dChg. capacity by the initial 0.5C dChg. capacity and multiplying by 100%.

Claims

Claim 1 As a composite layer of the cathode, the composite layer comprises particles of a cathode active material (CAM); a solid electrolyte; and carbon fibers coated with an oxide material, wherein the oxide material is B2O3, Li3B 11 O 18 , Li4B2O5, Li6B4O9, LiBO2, Li3BO 3, Li2B4O7, Li3B7O 12 A composite layer of a cathode selected from the group consisting of LiB3O5, Li4SiO4, Li3PO4, Li2SiO3, LiPO3, Li2SO4, Li2WO4, Li2MoO4, Li2ZrO3, LiAlO2, and composite oxides thereof. Claim 2 A composite layer of a cathode according to claim 1, wherein the oxide material coated on the carbon fiber has a thickness of 1-70 nm. Claim 3 A composite layer of a cathode according to claim 1, wherein the particles of the cathode active material (CAM) have a weight percentage of at least 65% in the composite layer. Claim 4 A composite layer of a cathode according to claim 1, wherein the carbon fiber coated with the oxide material has a weight percentage of 0.01 weight% to 5.0 weight% in the composite layer. Claim 5 A composite layer of a cathode according to claim 1, wherein the inorganic oxide material is stable in a voltage range from 1.9V to 5.0V. Claim 6 A composite layer of a cathode according to claim 1, wherein the solid electrolyte is an inorganic electrolyte containing sulfur. Claim 7 In claim 1, the solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiHa, Li2S-P2S5-P2O5, Li2S-Li3PO4-P2S5, Li3PS4, Li4P2S6, Li 10 GeP2S 12 , Li 3.25 Ge 0.25 P 0.75 S4, Li7P3S 11 , Li 3.25 P 0.95 S4, and Li 7-x PS 6-x Ha x A composite layer of a cathode selected from a group consisting of, wherein "Ha" is one or more halogen elements and 0.2 < x < 1.

8. Claim 8 A composite layer of a cathode according to claim 1, wherein the solid electrolyte has a weight percentage of 1% to 35% in the composite layer. Claim 9 In claim 1, the particles of the cathode active material (CAM) are Li x MO2, Li x Ni 1-y-z Co y M1 z O2 and Li x Ni 1-y-z Mn y M2 z At least one selected from the group consisting of O2, wherein M is at least one selected from the group consisting of Ni, Co, Mn, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, and rare earth elements; M1 is at least one selected from the group consisting of Mn, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, and rare earth elements; and M2 is at least one selected from the group consisting of Co, Al, B, Fe, Mg, Ca, Sr, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Rh, Pd, Cu, Zn, Cd, Ga, In, Sn, and rare earth elements, where 0.95 A composite layer of a cathode having ≤ x ≤ 1.1, 1-yz>0, 0< y ≤ 0.5, and 0 ≤ z ≤ 0.

5. Claim 10 An all-solid-state battery (ASSB), wherein the all-solid-state battery comprises: a) the composite layer of claim 1 as a positive electrode; b) a negative electrode; and c) a solid electrolyte layer between the positive electrode and the negative electrode. Claim 11 An all-solid-state battery (ASSB) according to claim 10, wherein the solid electrolyte layer is the same as or different from the solid electrolyte of the cathode composite layer. Claim 12 In claim 10, the all-solid-state battery (ASSB) has an initial discharge specific capacity of at least 180 mAh / g at a discharge rate of 0.5C. Claim 13 In claim 10, when the all-solid-state battery (ASSB) is charged to 4.25 V and discharged at 2.8 V for 20 cycles at 45°C with 0.1C in cycles 1 and 2, 0.33C in cycles 3 and 4, 1.0C in cycle 5, and 0.5C in cycles 6 through 20, the all-solid-state battery (ASSB) exhibits a specific capacity of at least 180 mAh / g and a cycle life retention rate of at least 95% in the 20th cycle, wherein the cycle life retention rate is the ratio of the discharge specific capacity in the 20th cycle to the initial discharge specific capacity at 0.5C at 45°C. Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete

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