Prelithiating Anode Active Material Particles 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 the solid electrolyte interface (SEI) layer, which limits the use of high-capacity anode materials and complicates battery manufacturing.
Innovation Solution
A process for producing prelithiated particles of anode active materials, where lithium is inserted into the anode active material particles before forming the anode electrode, using a lithiating chamber with a continuous process to achieve a high specific capacity and extended cycle life, and a protective polymer layer is applied to maintain particle integrity and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity anode materials (such as silicon, tin, germanium) are used to increase specific capacity, then the theoretical capacity increases significantly (up to 3500-4200 mAh/g), but the materials undergo severe mechanical degradation (pulverization and fragmentation) during charge-discharge cycles due to expansion and contraction
Solution Approach 1:
The patent applies preliminary lithiation by inserting lithium atoms into the anode active material particles before electrode formation. This pre-insertion of lithium compensates for the capacity loss due to SEI formation and reduces the mechanical stress during subsequent cycling, thereby extending cycle life while maintaining high specific capacity
Solution Approach 2:
The patent creates composite structures by combining anode active material particles with conductive additives and binder resins. This composite approach provides mechanical support to the high-capacity materials, preventing pulverization and fragmentation during expansion and contraction cycles
2Quantity of substance
If lithium metal is used as the anode active material to achieve high capacity, then the specific capacity is maximized, but safety concerns arise due to the formation of the solid electrolyte interface (SEI) layer and mechanical degradation
Solution Approach 1:
The patent extracts pure lithium metal and replaces it with lithium-ion intercalated anode active materials. This substitution eliminates the safety issues associated with lithium metal while maintaining high capacity through the use of high-capacity materials like silicon, tin, and germanium that can accommodate lithium ions
Solution Approach 2:
The patent creates a stable electrochemical environment by using lithium-ion intercalated materials instead of reactive lithium metal. The intercalated structure provides a more stable interface with the electrolyte, reducing the formation of unstable SEI layers and improving overall battery safety
3Object-affected harmful factors
If carbonaceous materials are used as anode active material to ensure safety, then safety is improved, but the specific capacity is limited (theoretical capacity of 372 mAh/g for graphite)
Solution Approach 1:
The patent creates composite anode structures combining carbonaceous materials with high-capacity materials such as silicon, tin, germanium, and their alloys. The carbonaceous component provides safety and structural stability, while the high-capacity materials contribute additional lithium storage capacity, achieving both safety and high performance
Solution Approach 2:
The patent merges the advantages of carbonaceous materials (safety, stability) with high-capacity materials (silicon, tin, germanium and their alloys). This combination allows the anode to achieve specific capacity beyond the limitation of pure graphite while maintaining the safety benefits of carbon-based structures
4Ease of manufacture
If conventional anode materials are used without prelithiation, then the manufacturing process is simpler, but the irreversible capacity loss is high due to SEI formation
Solution Approach 1:
The patent applies preliminary lithiation by inserting lithium atoms into the anode active material particles before electrode formation. This pre-insertion compensates for the lithium consumed during SEI formation, reducing irreversible capacity loss and improving overall battery efficiency
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 process results in a lithium-ion battery with significantly improved specific capacity and longer charge-discharge cycle life, reducing the need for additional electrodes and simplifying battery manufacturing by storing excess lithium within the anode active material, thereby minimizing SEI formation and enhancing stability.
Implementation Method 1
inserting a desired amount of lithium into the anode active material particles
Implementation Method 2
an electrolyte solution containing a lithium salt dissolved in a liquid solvent
Data Source
AI summary
Provided is a process for producing prelithiated particles of an anode active material for a lithium battery. The process comprises: (a) providing a lithiating chamber having at least one inlet and at least one outlet; (b) feeding a plurality of particles of an anode active material, lithium metal particles, and an electrolyte solution (containing a lithium salt dissolved in a liquid solvent) into the lithiating chamber through at least one inlet, concurrently or sequentially, to form a reacting mixture; (c) moving this reacting mixture toward the outlet at a rate sufficient for inserting a desired amount of lithium into the anode active material particles to form a slurry of prelithiated particles dispersed in the electrolyte solution; and (d) discharging the slurry out of the lithiating chamber through the at least one outlet.