Acid-Treated Cathode Sintering with Low-Melting Lithium Salt
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Solution Overview
Problem
High sintering temperatures in oxide solid-state battery production can cause chemical reactions between composite oxide particles and oxide solid electrolyte particles, leading to high resistance layers and energy inefficiency, necessitating a lower sintering temperature for the cathode.
Innovation Solution
Acid-treating lithium-containing composite oxide particles with a layered rock-salt structure and mixing them with a lithium salt having a lower melting point, followed by heating and sintering at a temperature below the reaction temperature with the oxide solid electrolyte, to facilitate efficient sintering and reduce interface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature sintering is used to sinter lithium containing composite oxide particles, then sintering can be achieved, but chemical reaction with oxide solid electrolyte particles occurs forming high resistance layers
Solution Approach 1:
The invention changes the sintering temperature parameter from conventional high temperatures (800-950°C) to low temperatures (300-600°C) by introducing a lithium salt additive. This parameter change enables sintering to proceed at temperatures below the reaction temperature with oxide solid electrolyte, preventing formation of high resistance layers while achieving adequate sintering density and electrical conductivity.
Solution Approach 2:
The invention introduces a lithium salt (such as lithium acetate, lithium formate, or lithium nitrate) as an intermediary substance that facilitates sintering at low temperatures. The lithium salt decomposes at relatively low temperatures to provide lithium ions that promote particle bonding, acting as a eutectic flux that enables sintering without requiring high temperatures that would cause harmful reactions with the oxide solid electrolyte.
2Manufacturing precision
If high sintering temperature is used, then sintering of cathode particles is achieved, but energy efficiency decreases
Solution Approach 1:
The invention dramatically reduces the sintering temperature parameter from 800-950°C to 300-600°C through the addition of lithium salt. This parameter change directly reduces the thermal energy input required for sintering, improving energy efficiency while still achieving adequate cathode densification and electrical conductivity for battery operation.
3Manufacturing precision
If conventional sintering methods are used, then cathode particles can be sintered, but sintering temperature must be as high as possible
Solution Approach 1:
The lithium salt serves as a eutectic flux intermediary that lowers the effective sintering temperature. The salt decomposes and creates a liquid phase that facilitates particle bonding at temperatures where conventional dry sintering would be ineffective, enabling adequate density achievement at 300-600°C rather than requiring 800-950°C.
Solution Approach 2:
The invention exploits the phase transition of the lithium salt from solid to liquid (melting) and subsequent decomposition at relatively low temperatures. This phase transition creates a liquid flux that enhances mass transport and particle bonding, enabling sintering at temperatures far below the conventional range while achieving adequate cathode density.
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 method allows for the sintering of lithium-containing composite oxide particles at lower temperatures, promoting efficient lithium diffusion and reducing interface resistance between the cathode and oxide solid electrolyte, thereby enhancing energy efficiency and battery performance.
Implementation Method 1
mixing the acid-treated particles with a lithium salt whose melting point is lower than that of the lithium containing composite oxide
Implementation Method 2
heating and sintering the mixture
Implementation Method 3
promoting efficient lithium diffusion
Data Source
AI summary
A method for producing a cathode that can lower a sintering temperature is provided. The method comprises: acid-treating particles of a lithium containing composite oxide that has a layered rock-salt structure; obtaining a mixture by mixing the acid-treated particles with a lithium salt whose melting point is lower than that of the lithium containing composite oxide; and heating and sintering the mixture.