Solid-State Battery Electrolyte Interface for Oxidation Resistance
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Solution Overview
Problem
Existing all-solid-state secondary batteries face challenges in maintaining charge and discharge characteristics due to oxidative decomposition of the solid electrolyte, leading to increased internal resistance and reduced capacity.
Innovation Solution
A battery design incorporating a positive electrode active material composed of Li, Ni, and Mn oxides, with a first solid electrolyte material containing Li, metalloid, or metal elements, and halogen elements, and a negative electrode primarily made of Bi, which suppresses oxidative decomposition and enhances charge and discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in all-solid-state secondary batteries, then the battery structure is simplified and safety is improved, but oxidative decomposition of the solid electrolyte occurs at high potentials, leading to increased internal resistance and reduced charge-discharge characteristics
Solution Approach 1:
A coating layer comprising a compound containing In as a cation and a halogen element as an anion is formed on the solid electrolyte surface. This coating layer acts as an intermediary protective barrier between the solid electrolyte and the positive electrode active material, preventing direct contact and oxidative decomposition while allowing ionic conduction to proceed.
Solution Approach 2:
The invention changes the chemical composition parameters of the solid electrolyte surface by introducing a coating layer with specific compositional characteristics (In cation and halogen anion compound). This compositional modification enables the solid electrolyte to withstand higher potentials without oxidative decomposition, allowing the use of high-potential positive electrode materials.
2Reliability
If the positive electrode active material potential is limited to 3.9 V or less versus Li, then oxidative decomposition of the solid electrolyte is suppressed, but the energy density and operating voltage of the battery are reduced
Solution Approach 1:
The coating layer of In-halogen compound serves as a protective intermediary that enables the battery to operate at potentials exceeding 3.9 V versus Li. By preventing direct oxidative decomposition through this intermediate layer, high-potential positive electrode active materials can be utilized, thereby increasing energy density while maintaining solid electrolyte stability.
3Ease of manufacture
If Bi is used as the main component of the negative electrode active material, then the negative electrode structure is simplified and cost is reduced, but the volume expansion during lithiation may affect battery performance
Solution Approach 1:
The invention applies a specific coating treatment to the Bi-based negative electrode particles, creating a localized protective layer on the particle surfaces. This local quality enhancement addresses the volume expansion issue at the particle level while maintaining the overall simplicity and cost-effectiveness of using Bi as the main negative electrode active material.
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 battery achieves improved charge and discharge characteristics, reduced internal resistance, and increased capacity by using Bi as the main component in the negative electrode and a Li, Ni, Mn oxide active material with a halogen-containing solid electrolyte, allowing for higher operating potentials and enhanced ionic conductivity.
Implementation Method 1
an electrolyte layer positioned between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode material, the positive electrode material includes a positive electrode active material and a first solid electrolyte material
Implementation Method 2
the positive electrode active material includes an oxide consisting of Li, Ni, Mn, and O
Data Source
AI summary
A battery according to the present disclosure includes: a positive electrode; a negative electrode; and an electrolyte layer positioned between the positive electrode and the negative electrode. The positive electrode includes a positive electrode material. The positive electrode material includes a positive electrode active material and a first solid electrolyte material. The positive electrode active material includes an oxide consisting of Li, Ni, Mn, and O. The first solid electrolyte material includes: Li; at least one selected from the group consisting of metalloid elements and metal elements except Li; and at least one selected from the group consisting of F, Cl, and Br. The negative electrode includes Bi as a main component of a negative electrode active material.