Rigid-Flexible Synergistic Buffer Layer Design in Mn/Co Bimetallic MOF-Derived Core-Shell Silicon-Based Anodes for...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon anodes are promising for high-energy lithium-ion batteries due to their high theoretical capacity.
• Severe volume expansion during cycling leads to rapid capacity fading and poor stability in silicon anodes.

Purpose of the Study:

• To develop a novel buffer layer strategy for silicon anodes to mitigate volume expansion and enhance electrochemical performance.
• To investigate the structural and electrochemical properties of silicon anodes with engineered composite buffer layers.

Main Methods:

• An in situ solvothermal method was used to synthesize Mn/Co bimetallic MOF (MC-BTC) precursors on silicon nanoparticles.
• Controlled pyrolysis transformed the precursors into carbon/MnO/CoO composite buffer layers, creating spherical shell architectures around silicon cores.
• Electrochemical performance was evaluated using galvanostatic cycling and rate tests.

Main Results:

• The engineered Si@MC-BTC-C composite exhibited a stable spherical shell architecture, effectively accommodating silicon volume expansion.
• The composite anode delivered a high reversible capacity of 1270 mAh g⁻¹ at 2 C.
• Remarkable cycling stability was achieved, retaining 806 mAh g⁻¹ after 1000 cycles at 10 C with a 0.06% decay rate per cycle.

Conclusions:

• The developed hierarchical composite buffer layer effectively addresses the volume expansion challenge in silicon anodes.
• This interfacial engineering approach significantly enhances the cycling stability and electrochemical performance of silicon-based anodes.
• The findings offer a promising pathway for the practical application of high-capacity silicon anodes in advanced energy storage systems.