Non-aqueous Electrolyte Additives for High-Voltage Lithium-Ion Batteries
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Solution Overview
Problem
Existing lithium ion batteries face challenges in achieving sufficient cycle performance and high-temperature storage performance, particularly under high voltage conditions, due to instability of the positive electrode structure and oxidative decomposition of the electrolyte, which leads to performance degradation and blockage of lithium ion diffusion channels.
Innovation Solution
A non-aqueous electrolyte for lithium ion batteries is developed, comprising a cyano-containing compound A and a compound B, which effectively inhibits the decomposition of the electrolyte and protects the positive electrode while forming a passivation film on the negative electrode, thereby enhancing cycle performance and high-temperature storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high voltage anode materials are used to improve energy density, then energy density is improved, but positive electrode structure stability deteriorates and electrolyte decomposition increases
Solution Approach 1:
The patent introduces a specific additive (containing fluorine, nitrogen, and oxygen atoms in specific ratios) as an intermediary substance that mediates between the high voltage positive electrode and the electrolyte. This additive forms a protective interface layer that prevents direct contact and harmful reactions between the electrode and electrolyte, thereby maintaining electrode structure stability while enabling high energy density operation.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte additive, specifically controlling the ratios of fluorine, nitrogen, and oxygen atoms, as well as the molecular weight distribution. These parameter changes optimize the protective film formation characteristics, enabling the system to achieve both high energy density and maintained electrode stability under high voltage conditions.
2Duration of action of moving object
If traditional film-forming additives (VC or FEC) are used, then cycle performance is improved, but high voltage stability deteriorates and high temperature storage performance worsens
Solution Approach 1:
The patent creates a composite electrolyte additive system that combines multiple chemical components with specific functional characteristics. This composite approach integrates the cycle performance enhancement capability of traditional additives with new functional groups that provide high voltage stability and improved high temperature storage performance, achieving synergistic effects that overcome the limitations of single-component additives.
3Use of energy by moving object
If operating voltage is increased to improve energy density, then energy density is improved, but electrolyte oxidative decomposition increases and lithium ion diffusion channels are blocked
Solution Approach 1:
The patent applies preliminary anti-action by introducing an additive that proactively prevents electrolyte decomposition before it occurs. The additive优先 reacts with the positive electrode surface to form a stable protective layer, which then acts as a barrier to prevent subsequent oxidative decomposition of the main electrolyte, thereby eliminating the harmful effects before they can degrade battery performance.
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 cyano-containing compound A and compound B in the non-aqueous electrolyte significantly improves the cycle performance and high-temperature storage performance of lithium ion batteries by reducing side reactions and maintaining electrode stability, resulting in better capacity retention and impedance control.
Implementation Method 1
forming a passivation film on the negative electrode
Implementation Method 2
the cyano-containing additive has an obvious complexing effect on Co ions in high oxidation state, thus inhibiting the continuous decomposition of electrolyte under high voltage
Data Source
AI summary
To address the existing problem of insufficient cycle performance and high-temperature storage performance of lithium ion battery electrolyte at high pressure, the disclosure provides a non-aqueous electrolyte for lithium ion battery. The non-aqueous electrolyte for lithium ion battery comprises a cyano-containing compound A and a compound B represented by formula I,The non-aqueous electrolyte for lithium ion battery provided by the disclosure contains both the cyano-containing compound A and the compound B, so that the lithium ion battery containing the non-aqueous electrolyte can have better cycle performance and high-temperature storage performance at high pressure.