Lithium Battery Electrolyte Composition for High-Temperature Cycle Life
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high-temperature lifetime and power output due to irreversible reactions and degradation of cathode and anode materials during charging and discharging, leading to reduced capacity and power output over cycles.
Innovation Solution
An electrolyte solution for lithium secondary batteries is developed, incorporating a lithium salt, solvent, and an additive 5-(4-cyanophenyl)-1-(4-fluorobenzyl)-1H-1,2,3-triazole-4-carbonitrile, which forms a solid electrolyte interface (SEI) on the anode and a cathode electrolyte interface (CEI), optimizing the battery's high-temperature stability and preventing material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional electrolyte solutions are used, then initial battery assembly is simple, but high-temperature lifetime is reduced due to irreversible reactions and material degradation
Solution Approach 1:
The patent applies preliminary action by introducing additives (vinylene carbonate and fluoroethylene carbonate) that form protective films (SEI and CEI) on the electrode surfaces before the battery undergoes high-temperature cycling. This pre-formed protective layer prevents subsequent degradation reactions, thereby extending high-temperature lifetime while maintaining capacity retention.
2Duration of action of stationary object
If protective films are formed on electrodes, then lifetime is increased and power output decrease is inhibited, but cell resistance may increase due to excessive film formation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration ratio of vinylene carbonate (0.5-3.0 wt%) and fluoroethylene carbonate (0.5-1.5 wt%) additives in the electrolyte. This optimization ensures the formation of protective films with appropriate thickness and composition, achieving sufficient protection against degradation while minimizing resistance increase from excessive film formation.
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 solution significantly increases the high-temperature lifetime of lithium secondary batteries, maintaining discharge retention of 84.6% or more after 50 cycles, while preventing excessive film formation that could increase cell resistance and ensuring sufficient film formation to enhance battery longevity.
Implementation Method 1
an additive that forms a CEI (cathode electrolyte interface) on a cathode and an SEI (solid electrolyte interface) on an anode
Implementation Method 2
an additive that forms a CEI (cathode electrolyte interface) on a cathode and an SEI (solid electrolyte interface) on an anode
Implementation Method 3
an electrolyte, which is a passage for lithium ions to move
Data Source
AI summary
The electrolyte solution for a lithium secondary battery includes: a lithium salt; a solvent; and an anode additive including 5-(4-cyanophenyl)-1-(4-fluorobenzyl)-1H-1,2,3-triazole-4-carbonitrile represented by Chemical Formula 1 below: