Non-Aqueous Li-Ion Battery Electrolyte for High-Nickel Cathode Cycling
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Solution Overview
Problem
Lithium ion secondary batteries with high nickel content lithium-containing composite oxides face challenges in achieving sufficient cycle characteristics due to increased charge transfer resistance and phase transitions at high states of charge, leading to degradation and cracking of the active material surface.
Innovation Solution
Incorporating a non-aqueous electrolytic solution with methylene methanedisulfonate at a concentration of 2.0% to 5.0% by mass, which forms a coating film on the active material surface, inhibiting cracking and decomposition, and using a lithium-containing composite oxide with a layered rock salt structure represented by LiNixCoyMnzO2, where 0.7≤x≤0.9, 0.05≤y≤0.2, and 0.05≤z≤0.15, to improve cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel content lithium-containing composite oxide is used as positive electrode active material, then energy density is improved, but cycle characteristics deteriorate due to increased charge transfer resistance and phase transitions
Solution Approach 1:
Methylene methanedisulfonate is introduced as an intermediary substance in the electrolytic solution that mediates between the high nickel content positive electrode active material and the electrolyte. It forms a protective coating film on the active material surface, preventing direct harmful interactions while allowing ionic transport, thus resolving the contradiction between high energy density and cycle stability
Solution Approach 2:
The chemical composition parameters of the electrolytic solution are changed by incorporating methylene methanedisulfonate at specific concentrations (2.0-5.0% by mass). This parameter change modifies the electrolyte's interaction with the high nickel content active material, reducing charge transfer resistance and preventing phase transitions during charge/discharge cycles
2Quantity of substance
If high nickel content lithium-containing composite oxide is used, then capacity is improved, but active material surface degradation and cracking occur
Solution Approach 1:
Methylene methanedisulfonate performs preliminary action by forming a protective coating film on the active material surface before degradation and cracking can occur. This pre-formed protective layer prevents subsequent surface degradation and maintains structural integrity during charge/discharge cycles
Solution Approach 2:
The coating film formed by methylene methanedisulfonate acts as an intermediary protective layer between the active material surface and the electrolyte, preventing direct contact and harmful reactions that would lead to surface degradation and cracking while maintaining high capacity
3Reliability
If methylene methanedisulfonate concentration is increased to form protective coating, then cycle stability is improved, but charge transfer resistance may increase
Solution Approach 1:
The concentration of methylene methanedisulfonate is optimized within a specific range (2.0-5.0% by mass) to achieve the right balance. At this optimized parameter setting, the coating film provides sufficient protection for cycle stability while maintaining adequate ionic conductivity to prevent excessive charge transfer resistance
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 methylene methanedisulfonate in the electrolyte solution forms a protective coating that enhances cycle stability and reduces charge transfer resistance, maintaining battery performance and capacity retention over multiple charge/discharge cycles.
Implementation Method 1
Incorporating a non-aqueous electrolytic solution with methylene methanedisulfonate at a concentration of 2.0% to 5.0% by mass, which forms a coating film on the active material surface
Implementation Method 2
the use of methylene methanedisulfonate in the electrolyte solution forms a protective coating that enhances cycle stability and reduces charge transfer resistance
Implementation Method 3
a positive electrode including a positive electrode active material capable of intercalating and deintercalating a lithium ion
Implementation Method 4
a non-aqueous electrolytic solution prepared by dissolving a lithium salt in a non-aqueous solvent
Data Source
AI summary
A non-aqueous electrolytic solution secondary battery including a positive electrode including a positive electrode active material capable of intercalating and deintercalating a lithium ion; a negative electrode including a negative electrode active material capable of intercalating and deintercalating a lithium ion; a non-aqueous electrolytic solution containing a lithium ion; and an outer package, wherein the positive electrode active material includes a lithium-containing composite oxide having a layered rock salt structure and represented by the following composition formula: LiNixCoyMnzO2, provided that 0.7≤x≤0.9, 0.05≤y≤0.2, 0.05≤z≤0.15, and x+y+z=1 are satisfied, and the battery is formed by using the non-aqueous electrolytic solution containing methylene methanedisulfonate and having a content thereof of 2.0% by mass or more and 5.0% by mass or less based on a solvent.