Halide-Coated Active Material for Oxidation-Resistant Solid-State Batteries
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Solution Overview
Problem
Conventional batteries with sulfide solid electrolytes face increased resistance due to oxidative decomposition during charging, particularly when the solid electrolyte has poor anti-oxidative stability, leading to inefficiencies in charge-discharge cycling.
Innovation Solution
A coated active material is developed with a halide solid electrolyte containing Li, Ti, and M (where M is Ca, Mg, Al, Y, or Zr), applied as a coating layer on the surface of the active material, ensuring a specific surface area ratio of less than 123% to achieve uniform coating and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a sulfide solid electrolyte is used in the battery, then ionic conductivity is improved, but oxidative decomposition occurs during charging leading to increased resistance
Solution Approach 1:
A coating layer comprising a halide solid electrolyte is applied on the surface of the active material to act as an intermediary between the sulfide solid electrolyte and the active material. This coating layer prevents direct contact and oxidative decomposition while maintaining ionic conductivity, thus resolving the contradiction between improving ionic conductivity and ensuring anti-oxidative stability.
Solution Approach 2:
The invention uses a composite structure combining a sulfide solid electrolyte (for high ionic conductivity) with a halide solid electrolyte coating layer (for anti-oxidative stability). This composite material approach allows the battery to benefit from both the high ionic conductivity of sulfide electrolytes and the oxidation resistance of halide electrolytes.
2Manufacturing precision
If the specific surface area ratio of coated active material to active material is increased, then coating coverage is improved, but manufacturing complexity increases
Solution Approach 1:
The invention specifies a quantitative parameter range for the specific surface area ratio (100% ≤ ratio < 123%) to ensure optimal coating coverage. By defining this parameter range, the patent simplifies the coating process control while ensuring uniform coverage, resolving the contradiction between coating precision and manufacturing complexity.
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 active material effectively suppresses oxidative decomposition, reducing battery resistance and enhancing durability by maintaining ionic conductivity and thermal stability, even with sulfide solid electrolytes, thereby improving charge and discharge efficiency.
Implementation Method 1
a coating layer including a first solid electrolyte, the coating layer coating at least a portion of a surface of the active material
Data Source
AI summary
A coated active material of the present disclosure includes: an active material; and a coating layer including a first solid electrolyte, the coating layer coating at least a portion of a surface of the active material. The first solid electrolyte includes Li, Ti, M, and F, the M is at least one selected from the group consisting of Ca, Mg, Al, Y, and Zr, and a ratio of a specific surface area of the coated active material to a specific surface area of the active material is smaller than 123%.