CoCO3 micrometer particles stabilized by carbon nanofibers networks as composite electrode for enhanced rate and cyclic performance of lithium-ion batteries

Abstract

The hybrids of metal-based materials supported by carbon nanofibers (CNFs) have potential application in reversible energy storage devices. In this work, four kinds of CoCO3 micrometer particles stabilized in the network of CNFs are designed and synthesized by using solvothermal method. The composite electrodes of cubic-CoCO3/CNF, spherical-CoCO3/CNF, spindle-CoCO3/CNF and dumbbell-CoCO3/CNF deliver the initial specific capacities of 1190, 987, 1193 and 1108 mAh g−1, respectively, and remain 503, 584, 666, 551 mAh g−1 at the 100th cycle. Bare spindle CoCO3 delivers the highest capacity of 1588 mAh g−1, but CoCO3 without the support of CNFs only remains 140 mAh g−1 at the 100th cycle. Spindle-CoCO3/CNF composite electrode exhibits the best rate performance, delivering 507 mAh g−1 at the current density of 1.0 A g−1. The ex-situ field emission scanning electron microscope (FESEM) images show that CNFs elastically buffer the volume change of CoCO3 during lithiation/delithiation cycles. CNFs as substrate play the important roles in providing excellent conductive channel to improve the rate capability and effective matrix buffering the volume change to promote the cyclic performance. This work presents a scalable approach to synthesize and optimize the hybrid structure of CoCO3/CNF for potential application in highly reversible lithium storage devices.