Amorphous Boron Solid Electrolyte for Lithium Battery Cycle Stability
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Solution Overview
Problem
All-solid type lithium batteries struggle to achieve high energy density and stability simultaneously, leading to insufficient charge and discharge cycles.
Innovation Solution
An electrode composite body is developed, comprising active material particles with lithium composite oxide, a first inorganic solid electrolyte, and a second inorganic solid electrolyte with boron, which is amorphous, enhancing charge mobility and structural uniformity, and a method of manufacturing this composite body involving impregnation and solidification processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystalline solid electrolyte is used, then ion conductivity can be improved, but mechanical deterioration occurs due to extension and contraction during charge and discharge cycles
Solution Approach 1:
The patent changes the physical state parameter of the solid electrolyte from crystalline to amorphous. The amorphous structure eliminates grain boundaries and crystal orientation issues, providing uniform ion conduction pathways that are less sensitive to mechanical stress from electrode expansion and contraction during cycling.
Solution Approach 2:
The patent creates a composite solid electrolyte system by combining amorphous inorganic solid electrolyte particles with a glassy matrix material. This composite structure provides both the ion conductivity needed for battery operation and the mechanical flexibility to accommodate volume changes without deteriorating.
2Quantity of substance
If high energy density is achieved, then battery capacity increases, but stability and cycle life become insufficient
Solution Approach 1:
The patent applies different material properties to different regions of the electrolyte system. The amorphous inorganic solid electrolyte provides high ion conductivity at the particle level for efficient lithium ion transport, while the glassy matrix provides mechanical stability and structural integrity at the macro level, enabling both high energy density and cycle stability.
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 electrode composite body enables a lithium secondary battery with stable charge and discharge cycles, improved reliability, and increased capacity and output, while the amorphous second electrolyte layer reduces mechanical deterioration and moisture sensitivity.
Implementation Method 1
the second inorganic solid electrolyte is amorphous, enhancing charge mobility and structural uniformity
Implementation Method 2
an electrolyte layer that is provided between layers of the positive electrode and the negative electrode and mediates lithium ion conduction therebetween
Data Source
AI summary
An electrode composite body includes: an active material molded body including active material particles which include a lithium composite oxide and have a particle shape, and a communication hole that is provided between the active material particles; a first solid electrolyte layer that is provided on a surface of the active material molded body, and includes a first inorganic solid electrolyte; and a second solid electrolyte layer that is provided on the surface of the active material molded body, and includes a second inorganic solid electrolyte of which a composition is different from a composition of the first inorganic solid electrolyte, and which contains boron as a constituent element and is amorphous.