Non-Aqueous Electrolyte Blends for Thick-Electrode Li-Ion Cells
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Solution Overview
Problem
Existing lithium ion batteries face challenges in achieving higher energy density and discharge rates, particularly as electrodes become thicker, necessitating improved electrolyte formulations to enhance electrochemical performance and capacity retention.
Innovation Solution
The development of a non-aqueous electrolyte solvent blend comprising ethylene carbonate (EC) and additional solvents like ethyl methyl carbonate (EMC) or propylene carbonate (PC) in specific volume ratios, along with lithium salts and optional additives, to form a stable solid electrolyte interphase (SEI) layer, improving discharge rates and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrodes are made thicker to increase energy density, then energy storage capacity is improved, but discharge rate capability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a boronic acid derivative additive in specific concentrations (0.1-5 wt% relative to lithium salt). This parameter change modifies the electrolyte's interaction with the electrode surface, enabling improved discharge rates even with thicker electrodes by optimizing ion transport kinetics at the electrode-electrolyte interface.
Solution Approach 2:
The patent creates a composite electrolyte system combining lithium salt, cyclic carbonate solvents (EC, PC), chain carbonate solvents (DMC, DEC, EMC), and boronic acid derivative additive. This composite formulation synergistically combines the high dielectric constant of cyclic carbonates, the low viscosity of chain carbonates, and the surface-modifying properties of the boronic acid additive, achieving both high energy density and high discharge rate capability.
2Ease of manufacture
If conventional electrolyte formulations are used with thicker electrodes, then manufacturing simplicity is maintained, but capacity retention deteriorates
Solution Approach 1:
The patent modifies the electrolyte composition by adding boronic acid derivative at controlled concentrations (0.1-5 wt% relative to lithium salt). This parameter adjustment improves capacity retention in thick electrodes by forming stable SEI layers that prevent electrode degradation during cycling, while maintaining compatibility with existing manufacturing processes.
Solution Approach 2:
The boronic acid derivative acts as an intermediary substance that mediates between the electrolyte and electrode surfaces. It forms protective interfacial layers that improve capacity retention and cycling stability, while the overall electrolyte formulation and application process remain compatible with conventional battery manufacturing methods.
3Power
If electrolyte composition is optimized for high discharge rates, then power capability is improved, but energy density deteriorates
Solution Approach 1:
The patent employs a composite electrolyte formulation that integrates multiple solvent types (cyclic and chain carbonates) with a boronic acid derivative additive. The cyclic carbonates (EC, PC) provide high dielectric constant for lithium salt dissolution, chain carbonates (DMC, DEC, EMC) provide low viscosity for fast ion transport, and the boronic acid additive provides surface stabilization. This composite approach achieves both high power capability and high energy density simultaneously.
Solution Approach 2:
The boronic acid derivative additive provides localized quality improvement at the electrode-electrolyte interface while the bulk electrolyte maintains properties optimized for energy density. The additive concentration (0.1-5 wt%) is sufficient to modify interfacial properties for high power capability without significantly affecting the bulk electrolyte's energy storage characteristics.
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 improved electrolyte formulations enhance discharge rate capability, especially at higher C-rates, and provide better capacity retention and cycling performance, suitable for high-energy, high-power applications such as electric vehicle propulsion.
Implementation Method 1
The development of a non-aqueous electrolyte solvent blend comprising ethylene carbonate (EC) and additional solvents like ethyl methyl carbonate (EMC) or propylene carbonate (PC) in specific volume ratios, along with lithium salts and optional additives, to form a stable solid electrolyte interphase (SEI) layer
Data Source
AI summary
Provided herein are improved electrolyte formulations. The improved performance may be realized as improved discharge rate cycling, improved capacity, improved Coulombic efficiency, or improved capacity upon cycling.