Sputtered LixPOy Coating on Ni Cathode for Solid State Battery Resistance
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Solution Overview
Problem
In the field of solid state batteries, there is a need to further reduce resistance in cathode active materials.
Innovation Solution
A method involving a coating step where a coating material represented by LixPOy (2≤x≤4, 3≤y≤5) is applied to a cathode active material containing Ni using a sputtering method, followed by heat-treating within 400° C. to 650° C. to diffuse the Ni element into the coating material, forming an amorphous coating portion that reduces resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is formed on the cathode active material surface using conventional methods (electrostatic atomizing, liquid phase, pulsed laser deposition), then the coating can be applied, but the resistance reduction effect is insufficient for solid state battery requirements
Solution Approach 1:
The invention changes the coating parameters by using sputtering method to deposit LixPOy coating material and subsequently heat treating at 400-650°C to achieve optimal resistance reduction. This parameter optimization (coating material composition, deposition method, heat treatment temperature) resolves the insufficiency of conventional coating methods in achieving adequate resistance reduction for solid state batteries
Solution Approach 2:
The invention creates a composite structure by forming a coating layer of LixPOy (where 2≤x≤4 and 3≤y≤5) on the cathode active material surface. This composite coating layer, with specific stoichiometric ratios, provides superior resistance reduction compared to conventional single-material coatings, directly addressing the insufficient resistance reduction effect
2Stability of the object's composition
If heat treatment is performed at high temperature to crystallize the coating layer, then the coating structure is improved, but the resistance increases
Solution Approach 1:
The invention optimizes the heat treatment temperature parameter to within 400-650°C, which is lower than conventional crystallization temperatures. At this optimized temperature range, the LixPOy coating layer achieves sufficient structural stability and Ni element diffusion without excessive crystallization that would increase resistance, thus resolving the contradiction between structural improvement and resistance increase
Solution Approach 2:
The invention creates a coating layer with specific local composition (LixPOy with controlled stoichiometry) that achieves the desired balance between structural stability and low resistance. The localized control of coating composition and heat treatment conditions allows the coating to maintain amorphous or fine-grained structure with low resistance while achieving sufficient stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces the resistance of the cathode active material for solid state batteries, enhancing its performance by inhibiting reactions with the solid electrolyte layer and maintaining stability at high voltages.
Implementation Method 1
a coating step of coating a coating material represented by LixPOy (2≤x≤4, 3≤y≤5) on a surface of a cathode active material containing an Ni element and being an oxide by using a sputtering method
Implementation Method 2
a heat-treating step of forming a coating portion in such a manner that the cathode active material coated with the coating material is heat-treated within a range of 400° C. to 650° C. to diffuse the Ni element into the coating material
Implementation Method 3
heat-treated within a range of 400° C. to 650° C.
Data Source
AI summary
A main object of the present invention is to provide a method for producing a cathode active material for a solid state battery, which is capable of reducing resistance. The present invention solves the problem by providing a method for producing a cathode active material for a solid state battery comprising steps of: a coating step of coating a coating material represented by LixPOy (2≤x≤4, 3≤y≤5) on a surface of a cathode active material containing an Ni element and being an oxide by using a sputtering method; and a heat-treating step of forming a coating portion in such a manner that the cathode active material coated with the coating material is heat-treated within a range of 400° C. to 650° C. to diffuse the Ni element into the coating material.