Lithium Battery Sulfur Distribution for High-Temperature Storage
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Solution Overview
Problem
Rechargeable lithium batteries face issues with increased resistance and gas generation during storage at high temperatures, which can lead to instability and reduced performance.
Innovation Solution
A rechargeable lithium battery design incorporating a positive electrode with a higher amount of sulfur than the negative electrode, along with specific additives, forms a thin sulfide layer that reduces resistance and gas generation, using a non-aqueous electrolyte and a high-nickel positive active material represented by Chemical Formula Li a1 Ni x1 Co y1 A z1 O 2, where sulfur in the positive electrode is between 0.01 wt% to 0.7 wt% and in the negative electrode is up to 0.33 wt% of the total battery weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rechargeable lithium battery is stored at high temperature, then the battery can be charged and discharged, but resistance increases and gas is generated leading to instability
Solution Approach 1:
A thin sulfide layer is formed on the surface of the positive active material particles through controlled sulfur addition (0.01-0.7 wt%). This sulfide layer acts as an intermediary protective coating that prevents direct contact between the positive active material and the electrolyte, thereby suppressing side reactions, resistance increase, and gas generation during high-temperature storage while maintaining electrochemical performance
Solution Approach 2:
The invention changes the chemical composition parameter by adding sulfur to form a sulfide layer on the positive active material surface. This parameter change (surface composition modification) fundamentally alters the interaction between the electrode and electrolyte, suppressing harmful reactions during high-temperature storage while maintaining battery functionality
2Reliability
If sulfur is added to the positive electrode to form a protective layer, then resistance increase is suppressed, but the battery composition becomes more complex
Solution Approach 1:
Sulfur is added locally to the surface of the positive active material particles rather than uniformly throughout the entire electrode or battery. This creates a localized sulfide layer (thin coating) on the particle surfaces that provides protective functionality without significantly altering the overall electrode composition or requiring complex manufacturing processes
Solution Approach 2:
A small amount of sulfur (0.01-0.7 wt% of total battery weight) is added to achieve the protective effect. This partial action approach uses minimal sulfur content to form a thin surface layer that is sufficient to suppress resistance increase and gas generation without over-complicating the battery composition
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 design effectively suppresses gas generation and resistance increase during high-temperature storage, maintaining battery stability and performance by inhibiting transition metal elution and minimizing side reactions.
Implementation Method 1
incorporating a positive electrode with a higher amount of sulfur than the negative electrode, along with specific additives, forms a thin sulfide layer that reduces resistance and gas generation
Implementation Method 2
utilizing materials capable of reversibly intercalating and deintercalating lithium ions as a positive active material and a negative active material
Data Source
Figure 1
AI summary
A rechargeable lithium battery and the rechargeable lithium battery including a positive electrode is provided. The positive electrode includes a positive active material and sulfur, a negative electrode comprising a negative active material and sulfur, and a non-aqueous electrolyte. An amount of sulfur in the positive electrode is at least twice an amount of sulfur in the negative electrode.