Interplay between inhomogeneous electrochemical reactions and mechanical responses in a silicon？graphite anode and its impact on cell degradation
- Nature Communications
Durability of high-energy throughput batteries is a prerequisite for enhanced market penetration of electric vehicles. Despite remarkable progresses in silicon anodes with high energy densities, rapid capacity fading of full cells has limited the use of silicon？graphite anodes. In this study, we unveiled degradation mechanism such as Li+ crosstalk between silicon and graphite, consequent Li+ accumulation in silicon, and capacity depression of graphite due to silicon expansion. The active material properties, i.e. silicon particle size and graphite hardness, were then modified based on these results to reduce Li+ accumulation in silicon and subsequent degradation of active materials in an anode. Finally, the cycling performance was tailored by designing electrodes to regulate Li+ crosstalk. Our findings provide insights into the electrochemistry of degradation mechanisms and a promising direction for the progressive improvement of materials and electrode designs for silicon？graphite anodes.
- Nature Communications volume 12, 2714 (2021)