Dual-Coated Positive Electrode Material for Halide Interface Resistance
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Solution Overview
Problem
Batteries using halide solid electrolytes in positive electrode materials experience increased internal and output resistance due to oxidative decomposition, particularly with elements like chlorine, bromine, and iodine, leading to inefficiencies in charging and discharging processes.
Innovation Solution
A coated positive electrode active material is developed, comprising a positive electrode active material with a first oxide solid electrolyte coating layer and a second coating layer containing Li, Ti, and F, where M is an element like Ca, Mg, Al, or Zr, which inhibits the formation of resistive layers at the interface with the halide solid electrolyte, reducing output resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If halide solid electrolyte is used in positive electrode material, then ionic conductivity is improved, but output resistance increases due to oxidative decomposition
Solution Approach 1:
An oxide coating layer is introduced as an intermediary between the positive electrode active material and the halide solid electrolyte. This coating layer prevents direct contact and oxidative decomposition while maintaining ionic conductivity, thus resolving the contradiction between improved ionic conductivity and increased output resistance
Solution Approach 2:
The positive electrode material is designed as a composite structure combining the positive electrode active material with an oxide coating layer. This composite structure maintains the high ionic conductivity of halide solid electrolyte while preventing oxidative decomposition, thereby reducing output resistance
2Reliability
If coating material is applied to positive electrode active material surface, then oxidative decomposition is inhibited, but device complexity increases
Solution Approach 1:
The oxide coating is applied locally only on the surface of the positive electrode active material particles rather than throughout the entire electrode structure. This localized approach provides protective functionality while minimizing added complexity in the overall device structure
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 coated positive electrode active material significantly reduces battery output resistance, enhancing charging and discharging efficiency and energy density while maintaining high ionic conductivity.
Implementation Method 1
Batteries using halide solid electrolytes in positive electrode materials experience increased internal and output resistance due to oxidative decomposition
Implementation Method 2
maintaining high ionic conductivity
Data Source
AI summary
A coated positive electrode active material includes a positive electrode active material, a first coating layer, and a second coating layer. The first coating layer coats at least a portion of a surface of the positive electrode active material. The second coating layer coats at least a portion of a surface of a fundamental active material, which includes the first coating layer and the positive electrode active material. The first coating layer contains an oxide solid electrolyte. The second coating layer contains Li, Ti, M, and F, where M is at least one element selected from the group consisting of Ca, Mg, Al, Y, and Zr.