Polyol Metal-Carbon Anode Layer for Dendrite-Resistant Solid Batteries
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Solution Overview
Problem
All-solid secondary batteries face issues with lithium dendrite growth through the solid electrolyte layer, leading to frequent short circuits, and the use of hydrophobic carbon materials results in poor bonding strength and dispersibility of anode active material layers.
Innovation Solution
An anode layer comprising a metal-carbon composite with a metal, carbon, and a polyol, where the polyol surface-modifies the carbon material to enhance bonding strength and reduce porosity, preventing lithium dendrite growth and improving the battery's lifespan and high-rate characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydrophobic carbon materials are used in the anode active material layer, then the electrical conductivity and capacity are improved, but the bonding strength and dispersibility deteriorate
Solution Approach 1:
A polyol binder is introduced as an intermediary substance between the hydrophobic carbon particles and the current collector. The polyol contains both hydrophilic groups (for bonding with current collector and electrolyte) and hydrophobic groups (for interaction with carbon particles), thereby mediating the interface between incompatible materials to achieve both good bonding strength and electrical conductivity
Solution Approach 2:
The chemical composition parameters of the binder are specifically optimized by selecting polyols with particular molecular weights and hydroxyl group densities. This parameter change allows the binder to simultaneously satisfy the requirements for hydrophobic interaction with carbon particles and hydrophilic bonding with the current collector and electrolyte
2Productivity
If the porosity of the anode active material layer is increased to improve electrolyte penetration, then the ion transport is enhanced, but the structural stability and dendrite suppression deteriorate
Solution Approach 1:
The porosity parameter of the anode active material layer is precisely controlled within the range of 20-40%. This optimized parameter range balances the competing requirements: sufficient porosity to allow electrolyte penetration and ion transport, while maintaining enough structural density to prevent lithium dendrite growth and ensure structural stability
3Quantity of substance
If the content of metal particles in the metal-carbon composite is increased to improve capacity, then the energy density is enhanced, but the bonding strength and dispersibility deteriorate
Solution Approach 1:
The polyol binder serves as a mediating matrix that surrounds and binds metal particles, carbon particles, and conductive agents together. This intermediary binder prevents metal particle aggregation, enhances dispersibility throughout the composite, and maintains bonding strength even at high metal content levels
Solution Approach 2:
A quaternary composite material system is formed consisting of metal particles, carbon particles, conductive agents, and polyol binder. This composite structure allows high metal content (up to 80 wt%) to be achieved while maintaining structural integrity through the synergistic combination of all four components
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 anode layer with a metal-carbon composite effectively suppresses lithium dendrite growth, enhancing the battery's voltage, capacity, and lifespan while maintaining high bonding strength and dispersibility, thus improving the overall performance of all-solid secondary batteries.
Implementation Method 1
the polyol surface-modifies the carbon material to enhance bonding strength and reduce porosity
Data Source
AI summary
An anode layer for all-solid secondary batteries, an all-solid secondary battery, and a method of manufacturing an all-solid secondary battery, the anode layer including an anode current collector; and a first anode active material layer on the anode current collector, wherein the first anode active material layer includes a metal-carbon composite including a metal, carbon, and a polyol.