Battery Electrolyte Additive for Stable Lithium Supplementation
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Solution Overview
Problem
The oxidation reaction between lithium iron oxide and oxygen during delithiation leads to electrolyte consumption and instability, reducing the cycling life and safety performance of batteries, while insufficient lithium release by lithium iron oxide compromises cycling performance.
Innovation Solution
Incorporating a cyclic compound with two sulfonate groups as a first additive in the electrolyte, which is more prone to redox reactions, forms protective films on electrode surfaces to suppress side reactions and stabilize the electrolyte, maintaining battery stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If lithium iron oxide is used as lithium supplement agent, then cycling performance is improved, but electrolyte stability deteriorates due to oxidation reactions
Solution Approach 1:
The patent introduces a cyclic compound with two sulfonate groups as an intermediary substance in the electrolyte. This compound mediates between the lithium iron oxide and the electrolyte by forming protective films on electrode surfaces, preventing direct harmful oxidation reactions while allowing lithium supplement functions to proceed. The cyclic compound acts as a buffer that enables both cycling performance improvement and electrolyte stability.
Solution Approach 2:
The patent converts the harmful oxidation reaction between lithium iron oxide and electrolyte into a beneficial process by controlling it to occur preferentially with the cyclic compound additive rather than the main electrolyte. The oxidation that would normally damage the electrolyte is redirected to form protective films through the cyclic compound, transforming a harmful effect into a protective mechanism.
2Duration of action of moving object
If lithium iron oxide releases lithium ions, then cycling performance is improved, but side reactions with electrolyte increase
Solution Approach 1:
The cyclic compound with two sulfonate groups serves as an intermediary that intercepts reactive species generated by lithium iron oxide during lithium release. By forming protective films on electrode surfaces, it prevents these reactive species from engaging in harmful side reactions with the bulk electrolyte, thereby enabling sustained cycling performance without excessive side reactions.
3Reliability
If cyclic compound additive is added to electrolyte, then electrolyte stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise parameter ranges for the cyclic compound additive (mass fraction w1 satisfying 0.01%≤w1≤2%) to achieve electrolyte stability improvement. By defining specific compositional parameters, the patent balances the need for stability enhancement with manufacturing feasibility, ensuring the additive concentration is sufficient for protection but low enough to maintain ease of manufacture.
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 cyclic compound additive enhances battery stability and safety by preventing side reactions and forming protective films, thereby improving capacity retention and energy efficiency.
Implementation Method 1
Incorporating a cyclic compound with two sulfonate groups as a first additive in the electrolyte, which is more prone to redox reactions, forms protective films on electrode surfaces to suppress side reactions and stabilize the electrolyte
Data Source
AI summary
A battery includes a negative electrode, a separator, a positive electrode, and an electrolyte. The electrolyte includes a first additive with a structural formula (1), where R1 is selected from a group consisting of H, CnH2n+1, and C6H5, and R2 is selected from a group consisting of H, CnH2n+1, and C6H5, with n satisfying 1≤n≤10. A mass fraction w1 of the first additive in the electrolyte satisfies 0.01%≤w1≤2%. A mass fraction of lithium supplement particles in a positive active layer of the positive electrode is w3, the lithium supplement particle includes a matrix and a coating layer, a plane shrinkage rate α of the matrix satisfies 0.4≤α×w3/w1≤1.7. A chemical formula of the matrix is Li1+rM1−pNpO4−sBs, with r satisfying 0.1<r<6.1, p satisfying 0≤p<0.99, and s satisfying 0≤s<0.1.