Surface-Stabilized Anode Particulates for Lithium Batteries
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Solution Overview
Problem
Lithium-ion batteries face challenges with mechanical degradation of anode active materials leading to shortened cycle life, high irreversible capacity, and safety concerns due to the formation of solid electrolyte interface (SEI) layers, which limits the choice of cathode active materials and complicates battery production.
Innovation Solution
A surface-stabilized anode active material particulate with a protecting polymer layer and prelithiated anode active material particles, coated with carbon or graphene, to enhance lithium ion conductivity and maintain particle integrity, reducing SEI formation and increasing cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbonaceous materials are used as anode to replace pure lithium metal, then safety is improved, but energy density is reduced
Solution Approach 1:
The patent uses composite anode materials combining carbonaceous materials with lithium alloys (such as Li-Si, Li-Sn, Li-Al) to achieve both safety and high energy density. The composite structure allows the anode to maintain the safety advantages of carbonaceous materials while incorporating high-capacity lithium alloy components that increase energy density through reversible lithium insertion and alloying reactions.
2Use of energy by moving object
If alloy particles are used to increase capacity, then specific capacity is improved, but mechanical degradation occurs leading to shortened cycle life
Solution Approach 1:
The patent employs thin film coatings (such as carbon coatings, oxide layers, or alloy interlayers) on the anode particles to provide mechanical protection. These flexible thin films accommodate the expansion and contraction of the alloy particles during lithium insertion and extraction, preventing pulverization and maintaining particle integrity over many charge-discharge cycles while preserving the high specific capacity of the alloy material.
Solution Approach 2:
The patent creates composite anode structures where high-capacity alloy particles are embedded in a matrix of carbonaceous material or conductive polymer. This composite architecture provides mechanical support and prevents degradation of the alloy particles, while the conductive matrix maintains electrical connectivity, thereby extending cycle life without sacrificing specific capacity.
3Reliability
If SEI layers are formed on anode, then electrochemical stability is improved, but irreversible capacity loss increases
Solution Approach 1:
The patent employs preliminary lithium insertion (pre-lithiation) before the anode is assembled into the battery cell. This preliminary action compensates for the lithium that will be irreversibly consumed during SEI layer formation, ensuring that sufficient lithium remains available for reversible cycling. By pre-loading the anode with additional lithium, the patent offsets the irreversible capacity loss and maintains high electrochemical stability.
Solution Approach 2:
The patent modifies the composition and structure of the anode material to change the properties of the形成的 SEI layer. By using specific alloy compositions (such as Li-Si, Li-Sn) and surface treatments, the patent promotes the formation of a thinner, more stable SEI layer with lower lithium ion resistance and reduced irreversible lithium consumption, thereby decreasing irreversible capacity loss while maintaining electrochemical stability.
4Use of energy by moving object
If lithium alloys are used as anode material, then specific capacity is improved, but handling complexity increases due to safety concerns
Solution Approach 1:
The patent introduces carbonaceous materials and protective coatings as intermediary layers between the reactive lithium alloy particles and the external environment. These intermediary layers act as barriers that reduce the reactivity of the lithium alloys with moisture and oxygen, making the anode material safer and easier to handle during manufacturing and assembly while preserving the high specific capacity of the lithium alloys.
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 solution provides a lithium-ion battery with significantly improved specific capacity and extended cycle life, reducing irreversible capacity loss and simplifying battery production by eliminating the need for additional electrodes and handling complexities.
Implementation Method 1
a protecting polymer layer that wraps around, embraces or encapsulates the one or plurality of anode active material particles
Implementation Method 2
coated with carbon or graphene, to enhance lithium ion conductivity
Implementation Method 3
one or a plurality of anode active material particles capable of reversibly storing lithium ions during a charge or discharge of the battery
Data Source
AI summary
Provided is a surface-stabilized anode active material particulate (for use in a lithium battery), comprising: (a) one or a plurality of prelithiated or un-prelithiated anode active material particles (with or without a coating of carbon, graphene, or ion-conducting polymer); (b) a protecting polymer layer that wraps around, embraces or encapsulates the one or plurality of anode active material particles, wherein the protecting polymer layer has a thickness from 0.5 nm to 5 μm, and a lithium ion conductivity from 10−8 S/cm to 5×10−2 S/cm at room temperature and the protecting polymer layer contains a polymer selected from poly(ethylene oxide) (PEO), polypropylene oxide (PPO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF), poly bis-methoxy ethoxyethoxide-phosphazene, polyvinyl chloride, poly(vinylidene chloride), polydimethylsiloxane, poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), polyethylene glycol (PEG), a PEG derivative, polyethylene glycol methyl ether, polyethylene glycol dimethyl ether, a sulfonated polymer, or a combination thereof.