Germanium Organyl Electrolyte Additive for High-Voltage NCM Batteries
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Solution Overview
Problem
Conventional lithium-ion battery electrolytes based on lithium hexafluorophosphate in carbonates exhibit low oxidative stability, leading to electrolyte decomposition and cathode material degradation at high potentials, resulting in low cycle stability and battery life.
Innovation Solution
Incorporating a germanium organyl-based electrolyte additive, such as 3,3'-((diphenylgermanediyl)bis(oxy))dipropanenitrile, into the electrolyte of lithium-ion batteries with lithium nickel manganese cobalt oxide (NCM) cathodes to enhance electrochemical stability and prevent cathode material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes based on lithium hexafluorophosphate in carbonates are used, then the battery can operate with standard components and manufacturing processes, but the electrolyte exhibits low oxidative stability leading to decomposition and cathode material degradation at high potentials
Solution Approach 1:
The patent introduces a germanium organyl-based additive as an intermediary substance that mediates between the electrolyte and the cathode material. This additive forms a protective interface layer that prevents direct contact and harmful reactions between the electrolyte and cathode, thereby suppressing electrolyte decomposition and cathode material degradation while maintaining electrochemical stability.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating specific germanium organyl compounds with particular molecular structures (containing Ge-C, Ge-O, or Ge-N bonds). This parameter change in the electrolyte composition fundamentally alters its oxidative stability characteristics, enabling it to resist decomposition at high potentials up to 4.5 V versus Li/Li+.
2Use of energy by moving object
If high potential operation (4.5 V vs Li/Li+) is achieved with NCM cathodes, then energy density is improved, but electrolyte decomposition and cathode material degradation occur
Solution Approach 1:
The germanium organyl-based additive performs preliminary protective action by forming a stable interface layer on the cathode surface before harmful decomposition reactions can occur. This pre-formed protective layer prevents subsequent degradation of both the electrolyte and cathode material during high-potential cycling, thereby enabling sustained energy density without compromising cycle stability.
Solution Approach 2:
The patent converts the potentially harmful high-potential operation (which normally causes decomposition) into a beneficial effect. By using the germanium organyl additive, the high potential of 4.5 V versus Li/Li+ is transformed from a degradation-inducing condition into an enabling condition for high energy density operation with improved cycle stability, as the additive stabilizes the interface under these harsh conditions.
3Reliability
If the electrolyte is made more stable against oxidation, then cathode material degradation is suppressed, but the electrolyte composition becomes more complex
Solution Approach 1:
The patent applies local quality by introducing the germanium organyl-based additive only at the electrode-electrolyte interface where it is most needed for stability. Rather than fundamentally redesigning the entire electrolyte composition, the additive locally modifies the interface properties to provide enhanced oxidative stability and suppress cathode material degradation, thereby achieving improved reliability with minimal increase in overall system complexity.
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 germanium organyl-based additive increases cycle stability, suppresses cathode material degradation, and reduces self-discharge, enabling superior high-voltage cycling performance and extended battery life.
Implementation Method 1
the electrolyte further comprises a germanium organyl-based electrolyte additive... suppresses cathode material degradation
Implementation Method 2
reduces self-discharge... enabling superior high-voltage cycling performance
Data Source
Figure 1~2
AI summary
The present invention relates to a lithium battery comprising an anode comprising an active anode material, a cathode comprising an active cathode material comprising lithium nickel cobalt manganese cobalt oxide (NCM), and an electrolyte separating anode and cathode, wherein the electrolyte comprises a solvent or solvent mixture and lithium hexafluorophosphate, wherein the electrolyte further comprises a germanium organyl-based electrolyte additive. Moreover, the present invention further relates to the use of the germanium organyl-based electrolyte additive in the lithium battery for enhancing one characteristic selected from the group consisting of reversible capacity, Coulombic efficiency, cyclic stability and combinations thereof.