Lithium Battery Electrolyte Additives for Manganese Cathode Life
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Solution Overview
Problem
Lithium secondary batteries using manganese as a cathode active material face challenges in achieving extended battery life, as they typically have shorter lifespans compared to those using cobalt or nickel, and there is a need for cost-effective and abundant alternatives to meet growing demand, especially in large-size battery applications.
Innovation Solution
A non-aqueous electrolytic solution containing an unsaturated sultone, vinylene carbonate, or its derivative, and a silyl phosphate derivative is used in conjunction with a composite oxide cathode active material where at least 35% of the transition metal is manganese, enhancing battery performance and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manganese is used as the main cathode active material to reduce cost and increase resource availability, then battery cost is reduced and resource abundance is improved, but battery life becomes shorter
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing specific additives (sultone compound at 0.01-5 wt%, vinylene carbonate at 0.1-5 wt%, and silyl phosphate derivative at 0.1-5 wt%) to modify the electrolyte's interaction with the manganese cathode, thereby improving battery life without changing the cathode material composition
Solution Approach 2:
The patent uses electrolyte additives as intermediary substances that mediate between the manganese cathode and the electrolyte. These additives form protective films on the cathode surface, preventing direct harmful interactions while allowing ionic transport, thus extending battery life without sacrificing the cost advantages of manganese
2Reliability
If conventional electrolytes are used with manganese cathode to maintain simplicity, then device complexity is reduced, but battery life and performance deteriorate
Solution Approach 1:
The patent applies partial action by adding small amounts (0.01-5 wt% each) of specific functional additives to the electrolyte rather than completely reformulating the electrolyte system. This partial modification is sufficient to achieve the desired life extension while maintaining the overall simplicity of the electrolyte composition
3Productivity
If manganese cathode is used to meet market demand for large-size batteries, then productivity and market adaptability are improved, but battery life and reliability worsen
Solution Approach 1:
The patent modifies the electrolyte composition parameters by adding specific functional additives that address the reliability issues of manganese cathodes, enabling manganese-based batteries to meet both current market demands and future requirements for extended life in large-size applications
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 proposed solution effectively extends the life of lithium secondary batteries by suppressing anode decomposition, reducing capacity loss, and inhibiting interfacial impedance, thereby improving load characteristics and high-temperature storage performance.
Implementation Method 1
the nonaqueous electrolyte contains a compound having a functional group of formula -SiR1R2R3... and a sultone having an unsaturated hydrocarbon group
Implementation Method 2
the non-aqueous electrolytic solution further comprising: vinylene carbonate, or a vinylene carbonate derivative, represented by following Formula (3), in an amount from 0.001% by mass to 10% by mass
Implementation Method 3
the non-aqueous electrolytic solution further comprising a silyl phosphate derivative represented by following Formula (4)
Data Source
AI summary
The present invention provides a non-aqueous electrolytic solution for a lithium secondary battery, wherein the lithium secondary battery includes, as a cathode active material, a composite oxide in which at least 35% by mole of a transition metal included in the composite oxide is manganese, and wherein the non-aqueous electrolytic solution includes an unsaturated sultone.