Minimizing carbon particle size to improve lithium deposition on natural graphite

Abstract

Carbon has been used as substrates for lithium deposition due to the affinity of the pre-lithiated carbon to the deposited lithium. However, co-intercalation of the solvated lithium ions results in severe particle exfoliation and pulverization of the graphitic carbon in the ether electrolytes. These problems will occur when graphite is used as the substrate for lithium deposition in the secondary batteries. Herein, we improve the structural stability of the carbon substrate and the lithium plating/stripping cycling on it by ball milling the natural graphite. Ball milling reduces the particle size, generates micropores and surface defects, suppresses the particle pulverization upon lithium deposition and significantly reinforces the lithium plating/stripping cycling. Reduction of the particle size effectively decreases the stress and strain upon co-intercalation of the solvated lithium ions and alleviates the particle pulverization in both the ether electrolyte and the carbonate electrolyte. Our findings suggest that minimizing (nano-sizing) the carbon particle or damaging the graphitic structure to some extent is beneficial for integrating the structure and enhancing the lithium plating/stripping cyclability of the graphite.