Prelithiated Anode Comminution for Cycle Life
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Solution Overview
Problem
Lithium-ion batteries face issues with mechanical degradation of anode active materials leading to shortened cycle life due to pulverization and fragmentation, and the need for a stable anode that does not require a sacrificial electrode or discrete lithium metal phase, while maintaining high specific capacity and minimizing irreversible capacity loss.
Innovation Solution
A method of producing a prelithiated anode active material by intercalating lithium into materials like silicon, tin, or their alloys, and then comminuting them into fine particles, which are combined with conductive additives and a binder to form an anode, allowing for rapid lithium ion penetration and maintaining contact with the current collector during charge-discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anode active materials are used in conventional form, then the battery can be assembled with standard materials, but the anode undergoes mechanical degradation and pulverization during charge-discharge cycles leading to shortened cycle life
Solution Approach 1:
The anode active material is divided into fine particles with average size less than 10 μm through comminution. This segmentation reduces the mechanical stress during lithium insertion/extraction cycles, preventing pulverization and maintaining structural integrity over many cycles, thereby improving cycle life while addressing mechanical degradation
Solution Approach 2:
The patent changes the particle size parameter of the anode active material from conventional larger sizes to fine particles less than 10 μm. This parameter change reduces brittleness and mechanical degradation during cycling, resolving the contradiction between maintaining mechanical stability and achieving long cycle life
2Quantity of substance
If lithium is intercalated into the anode active material, then the specific capacity is improved, but irreversible capacity loss occurs due to formation of solid electrolyte interface layer
Solution Approach 1:
The anode active material is prelithiated before being incorporated into the electrode. This preliminary action of adding lithium compensates for the irreversible capacity loss that occurs during the first charge cycle when the solid electrolyte interface layer forms, thereby maintaining high specific capacity while accounting for the inevitable energy loss
3Speed
If the anode active material is comminuted into fine particles, then lithium ion penetration is rapid and specific capacity is improved, but the particles may lose contact with conductive additives and current collector
Solution Approach 1:
A thin film coating is applied to the surface of the fine particles of anode active material. This coating acts as a flexible shell that maintains particle integrity and ensures continuous contact with conductive additives and current collector during charge-discharge cycles, preventing loss of contact while allowing rapid lithium ion penetration through the thin coating
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
This approach results in a lithium-ion battery with significantly improved specific capacity and extended cycle life, as prelithiated particles are more easily converted into nano-scaled particles, reducing brittleness and pulverization, and maintaining high capacity over many cycles without loss of contact with conductive additives and the current collector.
Implementation Method 1
intercalating lithium into an anode active material to produce a prelithiated anode active material
Implementation Method 2
comminuting the prelithiated anode active material into fine particles with an average size less than 10 μm
Implementation Method 3
a non-aqueous lithium ion-conducting electrolyte
Data Source
AI summary
A method of producing a lithium-ion battery anode comprising: (a) providing an anode active material; (b) intercalating or absorbing a desired amount of lithium into this anode active material to produce a prelithiated anode active material; (c) comminuting the prelithiated anode active material into fine particles with an average size less than 10 μm (preferably sub-micron and more preferably <200 nm); and (d) combining multiple fine particles of prelithiated anode active material with a conductive additive and/or a binder material to form the anode. The battery featuring such an anode exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.