Li-Rich Cathode Sacrificial Salts for First-Cycle Lithium Loss
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Solution Overview
Problem
Conventional lithium-ion battery anodes are costly, cumbersome, and inefficient, leading to limited battery lifetime due to high first cycle active lithium losses and solid electrolyte interphase (SEI) formation, which hinders the widespread adoption of electric vehicles and portable electronic devices.
Innovation Solution
The use of sacrificial salts in cathodes for prelithiation, where salts like dilithium squarate, ketomalonate, and oxalate are oxidized during the first charge cycle to act as a lithium reservoir, compensating for initial lithium losses and improving cycle life performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium-ion battery anodes are used, then the battery can operate, but the battery lifetime is limited due to high first cycle active lithium losses and SEI formation
Solution Approach 1:
The patent applies preliminary action by incorporating sacrificial salts (such as Li2S, Li2Te, Li2Se) into the cathode structure before battery operation. These salts serve as a pre-positioned lithium reservoir that releases lithium ions during the first charge cycle, compensating for the lithium that will be lost to SEI formation on the anode. This advance preparation ensures sufficient lithium inventory is available for subsequent cycles, thereby extending battery lifetime without requiring additional lithium in the anode.
Solution Approach 2:
The patent changes the chemical composition parameter of the cathode by integrating sacrificial salts with specific lithium content into the cathode structure. This parameter change transforms the cathode from a simple energy storage component to a dual-function component that also serves as a lithium reservoir. The sacrificial salts undergo oxidation during charging, releasing lithium ions that compensate for anode lithium losses, thereby improving battery reliability and cycle life.
2Reliability
If sacrificial salts are added to cathodes for prelithiation, then cycle life is improved, but device complexity increases
Solution Approach 1:
The patent merges the energy storage function and the prelithiation function into a single cathode component. By incorporating sacrificial salts directly into the cathode structure, the design eliminates the need for separate prelithiation agents or additional battery components. The sacrificial salts are integrated at the molecular level within the cathode matrix, creating a unified structure that performs both electrochemical energy storage and lithium compensation functions simultaneously, thereby avoiding increased device complexity.
Solution Approach 2:
The cathode structure is designed with multi-functionality, serving both as the primary energy storage component and as a lithium reservoir for compensating anode lithium losses. The sacrificial salts embedded in the cathode provide this additional function without requiring separate dedicated components. This universal design approach improves cycle life while maintaining relatively simple device architecture, as the same cathode structure performs multiple critical functions.
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 enhances the cycle life and energy density of lithium-ion batteries by maintaining a stable lithium inventory, reducing SEI formation, and increasing capacity retention, making lithium-ion batteries more viable for electric vehicles and portable devices.
Implementation Method 1
salts like dilithium squarate, ketomalonate, and oxalate are oxidized during the first charge cycle to act as a lithium reservoir
Data Source
AI summary
Systems and methods for batteries comprising a cathode, an electrolyte, and an anode, wherein sacrificial salts and prelithiation reagents are added to the cathode as functional additives for electrochemical prelithiation.