Model Based Design of Composite Carbonaceous Anode for Li-Ion Battery for Fast Charging Applications

Abstract

Blending of the popular anodic material graphite with hard carbon is one of the suggested way to improve the rate capability and cycle life performance in Lithium ion batteries. Based on this concept, this work proposes a high-rate battery with optimal blend composition, which can undergo high charge rate with high cycle life durability. This is done by suitably blending the existing graphite based anode with low cost hard carbon material, which improves the rate limiting solid phase diffusion. In this paper, an electrochemical model is developed for cell comprising of electrode with multiple active materials. Simulation study confirms that the hard carbon layer on graphite matrix facilitates charge transfer and creates additional electronic conduction pathways. Electrochemical model is used to devise a generic methodology to optimally design lithium ion cell comprising of anode with multiple active materials. In particular, the optimal composition of 30% hard carbon (HC) and 70% natural graphite (NG) exhibits high rate charging capability compared to pure NG. Efficacy of the proposed solution is also shown by demonstrating the high rate capability of the battery fabricated in the laboratory and prediction from proposed model are in good quantitative accord with the test result.