Nonaqueous Electrode Potential Control for Full Discharge Stability
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Solution Overview
Problem
Nonaqueous electrolyte batteries face structural degradation and capacity reduction when fully discharged, leading to undesirable side reactions and decomposition of the electrolyte, necessitating a solution to maintain performance and minimize degradation.
Innovation Solution
A nonaqueous electrolyte battery design incorporating a positive electrode with vanadium pentoxide, first carbon black, and a first binder, and a negative electrode with a silicon-containing material, graphite, and second carbon black, ensuring a potential range of 2.5 to 3.5 V versus metal lithium, which stabilizes the electrodes and suppresses degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the battery is fully discharged to achieve high capacity utilization, then the energy output is maximized, but structural degradation in the positive and negative electrode active materials occurs, leading to side reactions and electrolyte decomposition
Solution Approach 1:
The patent changes the potential parameter of the negative electrode by selecting specific materials (silicon-containing material with graphite and carbon black) and adjusting their proportions, so that at 0V battery voltage the negative electrode potential is 2.5-3.5V versus Li. This parameter change prevents structural degradation while maintaining high capacity utilization.
Solution Approach 2:
The negative electrode uses a composite material system comprising silicon-containing material, graphite, and carbon black in specific proportions. This composite structure combines the high capacity of silicon with the stability of graphite and carbon black, preventing degradation during full discharge while maintaining energy output.
2Quantity of substance
If high-capacity materials like silicon-containing material are used in the negative electrode to increase capacity, then the energy storage capability is improved, but the structural degradation and side reactions during full discharge are exacerbated
Solution Approach 1:
The negative electrode employs a composite material system with silicon-containing material (30-70 wt%), graphite (20-50 wt%), and carbon black (5-20 wt%). This composite structure leverages the high capacity of silicon while graphite and carbon black provide structural stability and suppress side reactions, resolving the contradiction between high capacity and reduced harmful effects.
Solution Approach 2:
The patent controls the potential parameter of the negative electrode through material composition, ensuring it falls within 2.5-3.5V versus Li at 0V battery voltage. This parameter control prevents excessive degradation and side reactions while maintaining high capacity from the silicon-containing material.
3Quantity of substance
If the battery is designed for high capacity with vanadium pentoxide and silicon-containing materials, then the energy density is improved, but the degradation level increases after storage in full discharge state
Solution Approach 1:
Both electrodes use composite material systems: the positive electrode combines vanadium pentoxide with conductive agents and binders, while the negative electrode combines silicon-containing material with graphite and carbon black. These composite structures maintain high capacity while improving stability during storage in the full discharge state.
Solution Approach 2:
The patent optimizes the potential parameters of both electrodes by adjusting material compositions and ratios. The negative electrode potential is controlled to 2.5-3.5V versus Li at 0V battery voltage, which stabilizes the electrode structures and reduces degradation during storage while preserving high capacity.
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 low degradation levels and maintains practical performance even after storage in a full discharge state, with improved capacity retention and internal resistance stability.
Implementation Method 1
When the battery voltage is 0 V, the potential of each of the positive electrode and negative electrode is 2.5 to 3.5 V versus that of metal lithium
Data Source
AI summary
A nonaqueous electrolyte battery includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and negative electrode, and a nonaqueous electrolyte. The positive electrode includes vanadium pentoxide, a first carbon black, and a first binder. The negative electrode includes a silicon-containing material, graphite, a second carbon black, and a second binder. When the battery voltage is 0 V, the potential of each of the positive electrode and negative electrode is 2.5 to 3.5 V versus metal lithium.