Lithium-Supplementing Slurry for Anode
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Solution Overview
Problem
Lithium ion batteries face lithium loss due to the formation of a solid electrolyte interface film during charging, leading to decreased battery capacity and initial coulombic efficiency, especially with silicon-based or tin-based anodes, and conventional lithium supplementation methods are costly, inefficient, and pose safety risks due to the use of toxic solvents like N-methyl-2-pyrrolidone and uneven lithium distribution.
Innovation Solution
A lithium-supplementing slurry comprising lithium metal powder and prepolymer is used, where the prepolymer acts as both a dispersant and binder, allowing for uniform dispersion and polymerization under heating or lighting to enhance mechanical strength and reduce the need for toxic solvents, with controlled mass ratios and non-aqueous organic solvents to optimize lithium supplementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDF is used as binder and dissolved in NMP, then binding performance is improved, but production cost increases and toxicity increases
Solution Approach 1:
The patent replaces expensive and toxic PVDF/NMP binder system with a water-based binder system that is cheaper and non-toxic. The water-based binder uses common, inexpensive materials and eliminates the need for costly organic solvents, directly addressing both cost and toxicity issues while maintaining binding functionality.
Solution Approach 2:
The patent changes the fundamental parameter of the binder system from organic solvent-based (NMP) to water-based. This parameter change transforms the entire system's environmental and economic characteristics, eliminating toxicity associated with NMP while reducing material costs, all while preserving the essential binding function.
2Quantity of substance
If lithium powder is added to anode slurry, then lithium supplementation is achieved, but uniform mixing becomes difficult due to lithium floating
Solution Approach 1:
The patent introduces a water-based binder as an intermediary medium that facilitates uniform distribution of lithium powder throughout the anode slurry. The binder acts as a carrier that prevents lithium floating and ensures homogeneous mixing, solving the distribution uniformity problem while enabling effective lithium supplementation.
Solution Approach 2:
The patent modifies the local properties of the slurry by using a water-based binder system that creates appropriate viscosity and adhesion characteristics. This local modification ensures that lithium powder remains suspended and uniformly distributed in specific regions of the slurry, preventing floating and achieving homogeneous composition throughout the anode.
3Loss of substance
If conventional lithium supplementation methods are used, then lithium loss is addressed, but production cost increases due to solvent recycling requirements
Solution Approach 1:
The patent eliminates the need for expensive solvent recycling infrastructure by using a water-based binder system. Water is inexpensive and does not require complex recycling processes, directly reducing production costs while still achieving the goal of minimizing lithium loss through effective supplementation.
Solution Approach 2:
The water-based binder system is self-sufficient and does not require external recycling processes. The binder naturally maintains its functionality without needing complex recovery and reprocessing systems, simplifying manufacturing and reducing costs associated with solvent management while effectively addressing lithium loss.
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 lithium loss, improves anode mechanical strength, and lowers production costs while ensuring safer and more efficient lithium supplementation, with better control over lithium distribution and enhanced battery performance.
Implementation Method 1
the prepolymer in the present invention acts as a dispersant, and because of its small molecular weight, better dispersion effect can be achieved when it is mixed with lithium powder
Implementation Method 2
the prepolymers in the lithium-supplementing slurry polymerize under lighting or heating conditions to form a macromolecular polymer, which causes the anode plate to possess certain mechanical strength
Data Source
AI summary
The present invention provides a method of supplementing lithium for an anode used for lithium secondary battery. Particularly, the present invention relates to lithium-supplementing slurry and a method for preparing the same, as well as an anode prepared with the slurry and a lithium secondary battery including the same. In the present invention, the prepolymer is used as a binder for supplementing lithium, the process for preparing the prepolymer is easy to operate and has low cost; the lithium-supplementing method using said prepolymer is easy to operate and has low cost, and it is easy to control the amount of lithium supplemented.