Zwitterion-Induced Interfacial-Potential Regulation Stabilizes Micron-Sized Silicon Anodes in Quasi-Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Micron-sized silicon (μ-Si) offers high energy density for lithium-ion batteries but suffers from capacity fade due to uncontrolled interfacial issues.
• Heterogeneous ion transport and solid-electrolyte interphase (SEI) rupture limit the practical application of μ-Si anodes.

Purpose of the Study:

• To develop a quasi-solid-state electrolyte that regulates the interfacial-potential distribution at the μ-Si/electrolyte interface.
• To stabilize μ-Si anodes and enable long-term cycling in high-energy lithium-ion batteries.

Main Methods:

• In situ polymerization of 3-(1-vinyl-3-imidazolyl)propanesulfonate (VIPS) to form a zwitterion-modified polymer electrolyte (PVIPSE).
• Utilizing synergistic effects of imidazolium and sulfonate groups for electrostatic screening and Li+ coordination.
• Employing scanning electrochemical microscopy to visualize interfacial potential and SEI uniformity.

Main Results:

• PVIPSE effectively equalizes interfacial potential and homogenizes Li+ flux across the μ-Si anode.
• Li+-sulfonate coordination promotes the formation of a uniform, inorganic-rich SEI layer.
• Scanning electrochemical microscopy confirmed reduced interfacial heterogeneity and improved SEI uniformity, leading to stable cycling.

Conclusions:

• Interfacial-potential regulation is a viable strategy for stabilizing high-capacity alloying anodes like μ-Si.
• The zwitterion-modified PVIPSE electrolyte enables stable long-term cycling of μ-Si anodes in lithium-ion batteries.
• This approach offers an orthogonal design principle to solvation engineering and mechanical reinforcement for battery anode stabilization.