LFP Cathode Material With Halide Electrolyte Interface Protection
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Solution Overview
Problem
Existing batteries using halide solid electrolytes face efficiency issues due to oxidative decomposition of the electrolyte during charging, leading to reduced charge/discharge efficiency and increased interfacial resistance.
Innovation Solution
The use of a cathode material comprising lithium iron phosphate as the cathode active material and a first solid electrolyte material represented by LiaMβXγ, where M includes metalloid or metal elements other than Li, and X includes Cl, Br, or I, without sulfur, to enhance ionic conductivity and suppress oxidation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If halide solid electrolyte is used in the battery, then ionic conductivity is improved, but oxidative decomposition occurs during charging leading to reduced charge/discharge efficiency
Solution Approach 1:
A protective coating layer is applied to the cathode active material particles to serve as an intermediary barrier. This coating prevents direct contact and oxidative decomposition reactions between the halide solid electrolyte and the cathode active material during charging, while still allowing lithium ion transport to maintain ionic conductivity.
Solution Approach 2:
The chemical composition and physical properties of the cathode active material surface are modified through coating treatment. This changes the electrochemical stability parameters of the interface, making it resistant to oxidative decomposition of the halide solid electrolyte while preserving lithium ion conductivity.
2Use of energy by moving object
If halide solid electrolyte is used in the battery, then ionic conductivity is improved, but interfacial resistance increases due to oxide layer formation
Solution Approach 1:
The protective coating acts as an intermediary layer that prevents the formation of high-resistance oxide layers at the interface. It maintains low interfacial resistance by preventing direct oxidation reactions while allowing efficient lithium ion transport between the halide solid electrolyte and cathode active material.
Solution Approach 2:
The potential harmful oxidation reaction is converted into a beneficial protective mechanism. The coating material is specifically selected to form a stable, conductive interface layer that protects against further degradation while maintaining ionic conductivity, turning the interface reaction into a protective rather than harmful effect.
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 configuration improves the charge/discharge efficiency of the battery by reducing side reactions and oxide layer formation, thereby enhancing the battery's operational output and energy density.
Implementation Method 1
the first solid electrolyte material includes Li, M, and X... LiaMβXγ... improves the charge/discharge efficiency of the battery
Implementation Method 2
lithium iron phosphate... suppress oxidation reactions... charge/discharge efficiency
Data Source
AI summary
The present disclosure provides a cathode material which has improved charge/discharge efficiency; and a battery using the same. The cathode material includes a cathode active material and a first solid electrolyte material; and the first solid electrolyte material contains Li, M and X; however, does not include sulfur. M represents at least one element that is selected from the group consisting of metalloid elements and metal elements other than Li. X represents at least one selected from the group consisting of Cl and Br, and I. The cathode active material includes lithium iron phosphate.