O2-Type Cathode Composition for Stable All-Solid-State Battery Cycling
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Solution Overview
Problem
Existing all-solid-state batteries face challenges in improving cycle characteristics, which are essential for maintaining battery performance over multiple charge and discharge cycles.
Innovation Solution
The all-solid-state battery incorporates a positive electrode active material with an O2 type structure, composed of at least Li, Mn, Ni, and O, along with a sulfide solid electrolyte and a negative electrode containing elemental Si and a Li—Si alloy, with a specific mass ratio to enhance discharging capacity and cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional positive electrode active materials are used in all-solid-state batteries, then the battery can operate, but the cycle characteristics are insufficient
Solution Approach 1:
The patent changes the compositional parameters of the positive electrode active material by incorporating specific ratios of Li, Mn, Ni, and Co elements. This compositional optimization resolves the contradiction by achieving both reliable cycle characteristics and high discharging capacity retention through precise parameter control of the cathode material
Solution Approach 2:
The patent uses a composite positive electrode active material containing multiple transition metal elements (Mn, Ni, Co) along with Li and O. This composite approach resolves the technical contradiction by combining the benefits of different elements: Mn provides structural stability for cycle life, while Ni and Co enhance capacity, achieving both reliability and productivity
2Productivity
If the positive electrode active material contains multiple transition metal elements, then the discharging capacity improves, but the structural stability may deteriorate
Solution Approach 1:
The patent optimizes the compositional parameters by controlling the ratios of transition metal elements (Li: 0.1-0.5, Mn: 0.3-0.7, Ni: 0.05-0.3, Co: 0.05-0.3 in atomic ratios). This parameter optimization resolves the contradiction by finding the balance point where high capacity elements (Ni, Co) are present in sufficient amounts while structural stability elements (Mn) dominate the composition
Solution Approach 2:
The patent creates a composite positive electrode active material where Mn-rich composition provides structural stability framework, while embedded Ni and Co phases provide high capacity pathways. This composite structure resolves the contradiction by spatially distributing different functional elements within a stable Mn-based matrix
3Productivity
If elemental Si and Li-Si alloy are used in the negative electrode, then the capacity increases, but the volume expansion during cycling increases
Solution Approach 1:
The patent uses Li-Si alloy particles nested within a composite negative electrode structure containing elemental Si. This nested configuration resolves the contradiction by allowing the Li-Si alloy to provide high capacity while the surrounding elemental Si matrix accommodates volume expansion, creating a hierarchical structure where inner high-capacity material is protected by outer buffer 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
This configuration significantly improves the cycle characteristics of the all-solid-state battery, leading to better retention of discharging capacity over multiple cycles and enhanced overall battery performance.
Implementation Method 1
a solid electrolyte layer, wherein the solid electrolyte layer contains a sulfide solid electrolyte
Implementation Method 2
the positive electrode contains a positive electrode active material, and the positive electrode active material has an O2 type structure and contains at least Li, Mn, Ni and O as constituent elements
Implementation Method 3
the negative electrode may contain elemental Si as a negative electrode active material and a Li—Si alloy as a negative electrode active material
Data Source
AI summary
There is provided an all-solid-state battery including a positive electrode, a solid electrolyte layer, and a negative electrode, wherein the positive electrode contains a positive electrode active material, and the positive electrode active material has an O2 type structure and contains at least Li, Mn, Ni and O as constituent elements.