Binder Composition for Silicon Electrodes Mitigating Volume Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium batteries using silicon as an active material face significant challenges due to volume changes during charge and discharge, leading to reduced charge/discharge capacity and electrode structure destruction, which existing binder agents and coatings have not adequately addressed.
Innovation Solution
A binder agent composition containing polymers, bivalent to decavalent alcohols, and water is used to create a slurry composition that maintains the structural integrity of silicon-containing electrodes, enhancing their charge/discharge capacity and long-term capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as an active material to increase capacity, then electric capacity is increased, but volume change during charge/discharge destroys electrode structure and reduces charge/discharge capacity
Solution Approach 1:
The invention changes the chemical composition parameters of the binder agent by incorporating specific polymers (polyacrylic acid, polyacrylamide, carboxymethyl cellulose), bivalent to decavalent alcohols (ethylene glycol, propylene glycol, butylene glycol), and water in controlled ratios. This compositional parameter change enables the binder to chemically interact with silicon and accommodate its volume expansion/contraction during charge/discharge cycles, thereby maintaining electrode structural integrity and charge/discharge capacity retention while preserving the high capacity benefits of silicon
2Reliability
If thermosetting resin coating is applied to inhibit capacity reduction, then charge/discharge capacity is retained, but heating treatment at 400°C is required making manufacturing complex
Solution Approach 1:
The invention replaces the thermal curing mechanism (heating at 400°C) with a chemical binding mechanism. The binder agent composition uses polymers crosslinked by bivalent to decavalent alcohols to form a stable gel structure at room temperature or mild conditions, eliminating the need for high-temperature heating treatment while achieving the same protective effect of retaining charge/discharge capacity
Solution Approach 2:
The invention changes the curing temperature parameter from 400°C (thermosetting resin) to room temperature or mild heating conditions (binder agent composition). This parameter change is achieved by replacing the thermosetting resin chemistry with polymer-alcohol crosslinking chemistry that operates at lower temperatures, thereby simplifying the manufacturing process while maintaining the protective function
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 proposed binder agent composition effectively retains high charge/discharge capacity and long-term capacity of lithium electrodes using silicon as the active material, mitigating the volume change issues and structural degradation associated with silicon-based batteries.
Implementation Method 1
a composition, which contains polymers, a bivalent to decavalent alcohol for binding the polymers
Data Source
AI summary
An object of the present invention is to provide an excellent binder agent composition solving problems such as the decrease in a charge/discharge capacity that occurs in a case where a silicon-containing active material is used, a slurry composition and an electrode in which the binder agent composition is used, and a method for preparing the electrode. The present invention relates to "a binder agent composition containing (A) one or more kinds of polymers containing polyacrylic acid, (B) a bivalent to decavalent alcohol, and (C) water", "a slurry composition for lithium batteries, containing 1) a silicon-containing active material, 2) a conductive assistant, and 3) the binder agent composition", "an electrode for lithium batteries that has 1) a silicon-containing active material, 2) a conductive assistant, 3) a binder agent derived from the binder agent composition, and 4) a current collector", and "a method for preparing an electrode for lithium batteries, including coating a current collector with the slurry composition and drying the slurry composition after the coating".