Negative Electrode Predoping Method for Lithium Battery Gas Reduction
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Solution Overview
Problem
Lithium-ion rechargeable batteries using negative electrode active materials previously doped with lithium ions experience significant gas generation during charging, leading to variations in electrode distance and local degradation due to lithium dendrite formation.
Innovation Solution
A predoping method that reduces the potential of the negative electrode active material by doping it with lithium ions, followed by a post-doping modification process using a reactive compound to increase the potential, thereby reducing gas generation and preventing lithium dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If negative electrode active material is doped with lithium ions to reduce potential, then energy density is improved, but gas generation increases during charging
Solution Approach 1:
The patent applies preliminary action by conducting a predoping process before battery assembly to dope the negative electrode active material with lithium ions and reduce its potential. This preliminary doping prevents gas generation during subsequent charging by pre-establishing the desired electrochemical state, thereby resolving the contradiction between improving energy density and preventing gas generation
Solution Approach 2:
The patent changes the potential parameter of the negative electrode active material through controlled lithium ion doping. By adjusting the doping level to achieve a potential of 0.01 V or lower relative to lithium metal, the patent improves energy density while the subsequent potential increase through reactive compound treatment prevents gas generation, thus resolving the contradiction
2Productivity
If negative electrode active material potential is reduced to improve battery performance, then charging efficiency is improved, but lithium dendrite formation increases
Solution Approach 1:
The patent dynamically adjusts the potential parameter of the negative electrode active material through a two-stage process: first reducing it to 0.01 V or lower to improve charging efficiency, then increasing it through reaction with reactive compounds to prevent lithium dendrite formation. This parameter modulation resolves the contradiction between charging efficiency and reliability
Solution Approach 2:
The patent introduces reactive compounds (such as water, oxygen, or carbon dioxide) as intermediaries that react with lithium ions doped into the negative electrode active material. This intermediary reaction increases the potential and prevents lithium dendrite formation, thereby resolving the contradiction between improved charging efficiency and prevented lithium dendrite formation
3Quantity of substance
If negative electrode active material is pre-doped with lithium ions, then capacity is improved, but gas generation during charge increases
Solution Approach 1:
The patent performs preliminary doping of the negative electrode active material with lithium ions before battery assembly to increase capacity. By conducting this doping in a controlled manner and subsequently treating with reactive compounds to increase potential, the patent achieves high capacity while preventing gas generation during charging
Solution Approach 2:
The patent changes the potential parameter of the negative electrode active material after doping to prevent gas generation. By increasing the potential through reaction with reactive compounds, the patent maintains the high capacity achieved through doping while eliminating the harmful gas generation effect
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 method effectively reduces gas generation during charging, stabilizes the state of charge, and enhances the safety and energy density of the battery by minimizing lithium dendrite formation.
Implementation Method 1
a predoping process to dope the negative electrode active material with lithium ions
Implementation Method 2
a post-doping modification process to cause reaction between a reactive compound that is reactive with lithium ions and lithium ions doped into the negative electrode active material
Data Source
AI summary
A predoping method for a negative electrode active material to dope the negative electrode active material with lithium ions. The predoping method for a negative electrode active material includes: a predoping process and a post-doping modification process. In the predoping process, the negative electrode active material is doped with lithium ions, to thereby reduce a potential of the negative electrode active material relative to lithium metal. In the post-doping modification process, after the predoping process, reaction is caused between a reactive compound that is reactive with lithium ions and lithium ions doped into the negative electrode active material, to thereby increase the potential of the negative electrode active material relative to lithium metal. The potential of the negative electrode active material relative to lithium metal is 0.8 V or more at completion of the post-doping modification process.