Oxalate Electrolyte Additives for Stable Lithium-Rich Mn Oxide Cathodes
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Solution Overview
Problem
Batteries that cycle lithium ions using layered lithium-rich and manganese-based oxides (LMR) as electroactive materials face issues such as voltage decay, low coulombic efficiency, and irreversible capacity loss after repeated charge and discharge cycles.
Innovation Solution
The incorporation of an oxalate-based additive, specifically bis(2,2,2-trifluoroethyl) oxalate, into the electrolyte of lithium-ion batteries, which contains a lithium manganese-based oxide as the positive electrode material, to enhance cycling stability and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If layered lithium-rich and manganese-based oxides are used as electroactive materials to achieve high capacity, then capacity is improved, but voltage decay and irreversible capacity loss occur after repeated cycles
Solution Approach 1:
An oxalate-based additive is introduced as an intermediary substance in the electrolyte that mediates the interaction between lithium ions and the positive electrode. This additive forms a protective interface layer that prevents direct harmful reactions while allowing lithium ion transport, thereby resolving the contradiction between high capacity and cycling stability
Solution Approach 2:
The chemical composition and properties of the electrolyte are modified by adding oxalate-based compounds. This parameter change in the electrolyte system alters the electrochemical environment at the electrode interface, suppressing voltage decay and capacity loss while maintaining high capacity performance
2Quantity of substance
If lithium- and manganese-containing oxides are used to achieve high capacity, then capacity is improved, but coulombic efficiency decreases after repeated cycles
Solution Approach 1:
The oxalate-based additive acts as an intermediary that facilitates more efficient lithium ion transfer at the electrode interface. By forming a conductive protective layer, it reduces energy losses during charge-discharge cycles while maintaining high capacity, thereby improving coulombic efficiency
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 use of the oxalate-based additive significantly improves the cycle life of the batteries by maintaining higher capacity retention and stability of the positive electrodes, outperforming control electrolyte formulations after multiple charge-discharge cycles.
Implementation Method 1
The incorporation of an oxalate-based additive, specifically bis(2,2,2-trifluoroethyl) oxalate, into the electrolyte of lithium-ion batteries... to enhance cycling stability and capacity retention
Implementation Method 2
an ionically conductive electrolyte that provides a medium for the conduction of lithium ions between the positive and negative electrodes during discharge and charge of the batteries
Data Source
AI summary
A battery that cycles lithium ions includes a positive electrode comprising an electroactive material comprising a lithium- and manganese-containing oxide and an electrolyte infiltrating the positive electrode. The electrolyte includes an organic solvent, a lithium salt in the organic solvent, and an oxalate-based additive in the organic solvent. The oxalate-based additive includes at least one oxalate compound selected from the group consisting of bis(2,2,2-trifluoroethyl) oxalate, tert-butyl 2,2,2-trifluoroethyl oxalate, methyl 2,2,2-trifluoroethyl oxalate, ethyl 2,2,2-trifluoroethyl oxalate, bis(2-chloroethyl) oxalate, and diethyl oxalate.