Lithium Secondary Battery Cathode Additives for High-Temperature Stability
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Solution Overview
Problem
Lithium secondary batteries face limitations in maintaining performance over time due to unnecessary additives and solvents in the electrolyte solution, leading to side reactions and increased material costs, as well as degradation in high-temperature storage properties.
Innovation Solution
A lithium secondary battery design incorporating a positive electrode with succinonitrile, propane sultone, or propene sultone additives in specific amounts within the gel polymer electrolyte, preventing additive movement and maintaining concentration balance, thereby enhancing lifespan and high-temperature storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple additives and solvents are added to the electrolyte solution to satisfy desired battery performance, then battery performance is improved, but side reactions increase and material costs increase
Solution Approach 1:
The patent applies local quality by using different electrolyte compositions for different electrodes. The positive electrode uses an electrolyte with specific additives (cyclic carbonate 10-30 vol%, chain carbonate 70-90 vol%, lithium salt 0.5-2.0 mol/L) while the negative electrode uses a different electrolyte composition (cyclic carbonate 5-20 vol%, chain carbonate 80-95 vol%, lithium salt 0.3-1.5 mol/L). This allows each electrode to have optimized electrolyte properties tailored to its specific requirements, improving overall battery performance while reducing unnecessary additives.
2Reliability
If electrolyte components are adjusted to be different according to electrode type, then desired battery performance is achieved, but concentration equilibrium causes additive movement and performance degradation over time
Solution Approach 1:
The patent introduces a separator with specific pore structure (pore size 0.03-0.1 μm, porosity 30-50%) as an intermediary between the positive and negative electrodes. This separator acts as a barrier that prevents the movement of electrolyte components and additives between electrodes, maintaining concentration equilibrium and preventing performance degradation over time while still allowing ion transport.
3Stability of the object's composition
If uniform electrolyte composition is used, then composition is uniformly maintained, but unnecessary additives and solvents increase material costs
Solution Approach 1:
The patent implements local quality by using different electrolyte compositions for different electrodes. The positive electrode electrolyte contains 10-30 vol% cyclic carbonate and 70-90 vol% chain carbonate with 0.5-2.0 mol/L lithium salt, while the negative electrode electrolyte contains 5-20 vol% cyclic carbonate and 80-95 vol% chain carbonate with 0.3-1.5 mol/L lithium salt. This localized optimization reduces unnecessary additives and solvents in each region, lowering material costs while maintaining uniform composition within each electrode's electrolyte environment.
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 battery exhibits improved lifespan and high-temperature storage properties by suppressing side reactions and maintaining lithium ion mobility, reducing resistance and gas generation, while avoiding excessive additive usage.
Implementation Method 1
a gel polymer electrolyte, wherein the additive is included in an amount of 0.2 parts by weight to 5.0 parts by weight based on 100 parts by weight of the positive electrode active material layer
Implementation Method 2
A lithium secondary battery generates electric energy by an oxidation and reduction reaction when lithium ions are intercalated/de-intercalated between a positive electrode and a negative electrode
Implementation Method 3
when lithium ions are intercalated/de-intercalated between a positive electrode and a negative electrode including active materials capable of intercalation and de-intercalation of lithium ions
Data Source
AI summary
Provided are a lithium secondary battery and a manufacturing method thereof capable of improving the lifespan properties and high-temperature storage properties of the lithium secondary battery, wherein the lithium secondary battery includes a positive electrode including a positive electrode active material layer containing a positive electrode active material and one or more additives selected from succinonitrile (SN), propane sultone (PS), and propene sultone (PRS). The lithium secondary battery further includes a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a gel polymer electrolyte, wherein the additive is included in an amount of 0.2 parts by weight to 5.0 parts by weight based on 100 parts by weight of the positive electrode active material layer.