DIFFERENTIAL CAPACITY ANALYSIS, A TOOL TO EXAMINE THE PERFORMANCE OF GRAPHITES FOR Li-ION CELLS

摘要

In this work we have examined the differential capacity (dQ/dV) as a tool to investigate performance of graphites for Li-Ion cells. We have shown that a careful numerical differentiation of the galvanostatic raw data can yield a smooth yet accurate evaluation of the differential capacity. The analysis of the dQ/dV curve and peak de-convolution reveals a series of overlapping peaks, that each of them could be associated to a particular process. This approach enabled us to assign the different peaks to different processes, like the formation of SEI, the solvated Li co-intercalation and the effect of Li reaction with surface species. As the area under each peak results in the charge accumulated or released by each process in particular, quantitative analysis of the differential capacity might be a valuable tool in evaluating the performance of carbons used as electrodes in Li-ion batteries.