Boosting Li ion kinetics in H–Co3O4@CNT electrode by synergic design of CNT coating and hollow structure

Abstract

Although the term “synergy” is generally adopted to explain the performance improvement of lithium-ion batteries (LIBs), the interaction mechanism is ambiguous due to the great challenge in identifying the individual contribution of each factor. In this work, a carbon nanotube (CNT) wrapped hollow Co3O4 (H–Co3O4@CNT) anode material is fabricated to quantify the synergy kinetics contribution through galvanostatic intermittent titration technique (GITT) and cyclic voltammetry (CV) analyses. The H–Co3O4@CNT electrode delivers higher Li+ diffusion coefficients (DLi+) value of 10−9.44–10−8.78 cm2 s−1 and Li+ capacitive coefficients (CLi+) value of 10−8.34–10−7.68 cm2 s−1 than the other two electrodes during depth of discharge (DOD) process. Depending on the further individual DLi+ and CLi+ calculation of CNT coating, hollow structure and their synergy, it is proved that CNT coating plays a significant role in the overall kinetic performance of H–Co3O4@CNT electrode. However, the result also demonstrates that hollow structure does not always play a positive role in synergy kinetics contribution. This work provides a kinetics mechanism analysis and quantitative individual factor contribution strategy for design of advanced LIBs.