Differential voltage analysis for rapid and sensitive rate capability evaluation of graphite anodes

With the growing demand for fast-charging capabilities in lithium-ion batteries (LIBs), developing an effective method to evaluate the rate capability of graphite anodes has become crucial. This study introduces a novel differential voltage analysis (DVA) to assess the rate capability of graphite anodes by analyzing the Peak S2 intensity from the differential voltage (dV/dQ) profile during charging. The higher Peak S2 intensity gives rise to a uniform lithiation state and minimal Li ​ + ​concentration gradients, resulting in enhanced rate capability. The reliability of this method was substantiated by comparing it with traditional rate capability evaluations, which yielded consistent outcomes. Furthermore, this study delved into the relationship between rate capability and structural characteristics. It examined the correlation between the Peak S2 and key structural parameters of various commercial graphite samples. The results indicate that graphite with a smaller mean crystallite size along the a axis (L a ), a lower orientation index (OI) values, and a higher weight of high-graphitized phase (φ h ) exhibits accelerated lithium-ion diffusion and enhanced intercalation, hence a superior rate capability. This proposed method enables rapid prediction of rate capability and provides insights for material design, guiding the development of graphite anodes for fast-charging applications.