Electrolyte Composition for Lithium Secondary Battery
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Solution Overview
Problem
Lithium secondary batteries face issues with stability and lifespan characteristics when using high-voltage cathode active materials and anode active materials, particularly due to electrolyte decomposition and ion conductivity challenges, especially when using cyclic carbonates and linear solvents in specific ratios.
Innovation Solution
A non-aqueous electrolyte composition is developed, incorporating a cyclic carbonate within a specific weight range (1 wt% to 30 wt%), an anion receptor (tris(trimethylsilyl)borate), and a linear solvent, which stabilizes the battery performance by reducing electrolyte decomposition and enhancing ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a non-aqueous electrolyte containing cyclic carbonate and linear solvent is used in lithium secondary batteries with high-voltage cathode active materials, then ion conductivity is improved, but electrolyte decomposition occurs and lifespan characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the weight ratio of cyclic carbonate to linear solvent within 1:9 to 30:70, and by controlling the cyclic carbonate content at 1-30 wt% based on total non-aqueous solvent. This optimization resolves the contradiction by finding the optimal parameter range where ion conductivity is maintained while electrolyte decomposition is suppressed, improving both speed and reliability.
2Productivity
If the amount of cyclic carbonate in the electrolyte is increased to improve ion conductivity, then rate characteristics are enhanced, but electrolyte decomposition increases and stability at high voltage decreases
Solution Approach 1:
The patent resolves this contradiction through parameter changes by establishing the cyclic carbonate content range of 1-30 wt% of total non-aqueous solvent. This optimized parameter range enables the electrolyte to achieve sufficient ion conductivity for good rate characteristics while maintaining stability at high voltages, preventing excessive electrolyte decomposition.
3Ease of manufacture
If conventional electrolyte compositions are used with spinel-structure lithium nickel-based metal oxides, then manufacturing is simplified, but reaction at the electrode-electrolyte interface varies and performance is inconsistent
Solution Approach 1:
The patent applies parameter changes by optimizing the electrolyte composition parameters - specifically the cyclic carbonate to linear solvent ratio (1:9 to 30:70) and cyclic carbonate content (1-30 wt%). This creates a standardized, optimized composition that ensures consistent performance with spinel-structure lithium nickel-based metal oxides while remaining easy to 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 electrolyte composition improves the lithium secondary battery's lifespan and rate characteristics by maintaining stability at high voltages and reducing anode reduction, thereby enhancing overall battery performance.
Implementation Method 1
the non-aqueous solvent includes an anion receptor... which stabilizes the battery performance by reducing electrolyte decomposition
Implementation Method 2
the non-aqueous electrolyte acts as a medium through which lithium ions migrate between the anode and the cathode
Implementation Method 3
enhancing ion conductivity... improves the lithium secondary battery's lifespan and rate characteristics
Data Source
AI summary
Disclosed are an electrolyte for a lithium secondary battery which includes a non-aqueous solvent and a lithium salt, wherein the non-aqueous solvent includes an anion receptor, a cyclic carbonate, and a linear solvent, wherein an amount of the cyclic carbonate is in a range of 1 wt% to 30 wt% based on a total weight of the non-aqueous solvent, and a lithium secondary battery including the same.