Fluorinated Positive Electrode Coating for Low-Resistance Batteries
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Solution Overview
Problem
Existing positive electrode materials in batteries experience an increase in internal resistance during charge due to oxidative decomposition of halide solid electrolytes, particularly those containing chlorine, bromine, and iodine, which form a resistance layer and hinder lithium-ion conductivity.
Innovation Solution
Incorporating a positive electrode material with a first solid electrolyte coating that includes Li, Ti, and M1 (where M1 is Ca, Mg, Al, or Zr) to enhance oxidation resistance and ionic conductivity, thereby reducing interfacial resistance and suppressing internal resistance increases during charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halide solid electrolytes containing chlorine, bromine, or iodine are used in positive electrode materials, then ionic conductivity is improved, but oxidative decomposition occurs during charge forming a resistance layer that increases internal resistance
Solution Approach 1:
The patent introduces a fluorinated solid electrolyte coating layer as an intermediary between the positive electrode active material and the halide solid electrolyte. This coating layer acts as a protective barrier that prevents direct contact between the halide electrolyte and the positive electrode, thereby blocking the oxidative decomposition pathway while maintaining ionic conductivity. The fluorinated layer serves as a mediator that allows lithium ion transport without permitting harmful oxidation reactions.
Solution Approach 2:
The patent creates a composite structure combining fluorinated solid electrolyte material with halide solid electrolyte components. The fluorinated coating layer is applied over the positive electrode active material, forming a composite electrode structure that leverages the oxidation resistance of fluorinated compounds while maintaining the high ionic conductivity characteristics of halide electrolytes. This composite approach resolves the contradiction by integrating materials with complementary properties.
2Reliability
If fluorinated solid electrolyte coating is applied to prevent oxidative decomposition, then internal resistance stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the thickness and composition parameters of the fluorinated solid electrolyte coating to achieve effective protection at minimal complexity. By controlling the coating thickness within a specific range and adjusting the fluorinated compound composition, the patent achieves adequate protection against oxidative decomposition while keeping the coating process simple and the structure manageable. This parameter optimization balances performance improvement with manufacturing feasibility.
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
The proposed electrode material effectively suppresses internal resistance and improves battery output characteristics by maintaining high lithium-ion conductivity and reducing interfacial resistance through the use of fluorine-containing halide solid electrolytes with specific compositions.
Implementation Method 1
the first solid electrolyte material includes Li, Ti, M1, and F... effectively suppresses internal resistance and improves battery output characteristics by maintaining high lithium-ion conductivity and reducing interfacial resistance through the use of fluorine-containing halide solid electrolytes
Implementation Method 2
maintaining high lithium-ion conductivity and reducing interfacial resistance through the use of fluorine-containing halide solid electrolytes
Data Source
AI summary
A positive electrode material of the present disclosure includes: a positive electrode active material; and a first solid electrolyte material coating at least partially a surface of the positive electrode active material, wherein the first solid electrolyte material includes Li, Ti, M1, and F, and the M1 is at least one element selected from the group consisting of Ca, Mg, Al, Y, and Zr.