Lithium Battery Electrolyte Composition for Dendrite Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges in capacity improvement due to metallic lithium deposition in dendrite form, leading to side reactions and deteriorated cycle characteristics, particularly when using oxalate salts that accelerate positive electrode degradation.
Innovation Solution
Incorporating an oxalate salt with a polycyclic thiazole compound in the electrolyte, forming a SEI film that suppresses dendrite formation and positive electrode deterioration, thereby improving charge-discharge efficiency and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lithium secondary battery is charged at a high charge rate, then the charge time is reduced and productivity is improved, but lithium ion deposition occurs on the graphite negative electrode and battery reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-coating the negative electrode with a specific electrolyte composition containing cyclic carbonate (15-30 vol%) and chain carbonate (70-85 vol%) before high-rate charging. This pre-prepared electrolyte layer creates a stable SEI film in advance, preventing lithium ion deposition during subsequent high-rate charging operations, thus enabling both high productivity and maintained reliability
2Quantity of substance
If the electrolyte is heated to remove solvent, then the electrolyte concentration is improved, but lithium ion mobility deteriorates due to increased viscosity
Solution Approach 1:
The patent applies parameter changes by carefully controlling the heating temperature range (40-70°C) and time to achieve partial solvent removal that concentrates the electrolyte to optimal levels without excessive heating. This controlled parameter adjustment increases lithium salt concentration to improve ionic conductivity while maintaining lithium ion mobility, avoiding the viscosity increase that would occur with higher temperatures
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 combination of oxalate salt and polycyclic thiazole compound enhances the battery's cycle characteristics and charge-discharge efficiency by preventing dendrite formation and reducing positive electrode degradation.
Implementation Method 1
positive electrode and a negative electrode each having a specific composition and specific properties
Implementation Method 2
lithium secondary battery wherein electrodes of the battery have a specific composition and specific properties
Data Source
Figure 1
AI summary
A lithium secondary battery having a positive electrode, a separator, a negative electrode facing the positive electrode with the separator interposed therebetween, and an electrolyte, in which metallic lithium deposits on the negative electrode during charge. The electrolyte includes: an oxalate salt containing an oxalate complex as an anion, and a lithium ion as a cation; and a polycyclic compound having a thiazole ring and an aromatic ring sharing one side with the thiazole ring.