Electronic-State Engineering of Transition Metals Regulates Decomposition Kinetics of Li₂C₂O₄ for Cathode...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Lithium oxalate (Li2C2O4) is a potential prelithiation reagent for lithium-ion batteries.
• A major limitation is its high activation voltage (>4.6 V).
• Developing efficient catalysts is crucial for practical application.

Purpose of the Study:

• To establish a correlation between component-electronic structure and catalytic activity.
• To design and synthesize transition metal-loaded N,S co-doped carbon catalysts (M/NSC).
• To investigate the catalytic performance of M/NSC for Li2C2O4 activation.

Main Methods:

• Synthesis of M/NSC catalysts (M = Fe, Co, Ni, Ru, Rh, Ir).
• Characterization of catalyst electronic structures and metal-carbon interactions.
• Electrochemical testing of Li2C2O4 decomposition voltage and prelithiation performance.
• Application of optimized catalysts in LiFePO4 and NCM9055 cathode systems.

Main Results:

• Catalytic activity is dependent on the metal's electronic structure and interaction with the N,S co-doped carbon support.
• Fe-group metals showed stronger electronic coupling and higher redox flexibility, leading to more effective Li2C2O4 activation.
• Co/NSC exhibited the lowest decomposition voltage (4.17 V) due to uniform dispersion, optimized coordination, and charge transfer.
• The Co/NSC-Li2C2O4 composite demonstrated efficient decomposition and superior prelithiation.
• Application in LFP and NCM9055 cathodes resulted in a 22% capacity increase and an ICE enhancement from 77% to 85.6%.

Conclusions:

• Electronic structure engineering of M/NSC catalysts is an effective strategy for activating Li2C2O4.
• Co/NSC demonstrates excellent catalytic activity and enables practical lithium compensation.
• This approach significantly improves the performance of high-energy lithium-ion batteries.