Integrative Additive Design for Robust SEI Formation in NMC811||Silicon Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes offer high capacity for lithium-ion batteries (LIBs) but suffer from poor electrochemical performance.
• Functional additives are a cost-effective strategy to improve LIB anode properties.

Purpose of the Study:

• To systematically investigate the impact of various functional additives on the performance of silicon anodes in LIBs.
• To identify the most effective additive for enhancing the electrochemical properties of NMC811||Si full cells.

Main Methods:

• Systematic electrochemical testing of LiNi0.8Mn0.1Co0.1O2 (NMC811)||Si full cells with different additives.
• Characterization using Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS).

Main Results:

• Lithium difluorobis(oxalato)phosphate (LiDFBOP) demonstrated superior performance compared to other additives.
• LiDFBOP enabled the best capacity retention over 300 cycles in NMC811||Si full cells.
• Characterization revealed LiDFBOP forms a more stable solid electrolyte interphase (SEI) on the silicon anode.

Conclusions:

• LiDFBOP is a highly effective additive for improving silicon anode stability and performance in LIBs.
• The favorable molecular structure of LiDFBOP integrates beneficial features of other additives, leading to enhanced SEI formation.
• LiDFBOP shows significant promise for advancing silicon-based lithium-ion battery technology.