MOFs derived Co1−xS nanoparticles embedded in N-doped carbon nanosheets with improved electrochemical performance for lithium ion batteries

Abstract

Cobalt sulfides (including CoS, CoS2, Co3S4, Co9S8 and nonstoichiometric Co1−xS) are deemed to a kind of novel anode material for lithium ion batteries due to their large specific capacities. However, cobalt sulfides suffer from poor cycling stability with the large volume expansion. In this work, we designed and synthesized a novel Co-metal organic frameworks (MOFs) material by using carbazolyl carboxylates ligand H4DCDC. The Co1−xS nanoparticles embedded in N-doped carbon sheets (Co1−xS/NCS) composites are obtained via vulcanizing the Co-MOFs precursor. As a result, the Co1−xS/NCS exhibits outstanding cycling stability and maintains a high capacity of 796.3 mA h g−1 at the current density of 200 mA g−1 after 100 cycles. The N-doped carbon sheets can not only enhance the conductivity of materials but also buffer the volume expansion during charge-discharge process.