Energy Storage Materials 2018-03-22

MoS2 nanobelts with (002) plane edges-enriched flat surfaces for high-rate sodium and lithium storage

Zhenyu Zhang, Shuilin Wu, Junye Cheng, Wenjun Zhang

Index: 10.1016/j.ensm.2018.03.013

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Abstract

Two-dimensional (2D) transition metal chalcogenides (TMDs) have shown great potential as high-performance anode materials in lithium and sodium ion batteries (LIBs and SIBs). Due to the greater density of active sites on the edges of (002) planes and favorable insertion/desertion of Li/Na ions along the inter-planar direction, control on the crystal structures of 2D TMD has been demonstrated to be significant to their high-rate and stable-cycling performances. Here, we synthesized MoS2 nanobelts (NBs) with richly exposed (002) plane edges on their flat surfaces through in situ sulfuration of MoO3 NBs. In contrast to the conventional MoS2 nanosheets that exposed richly the (002) lateral surface, the MoS2 NBs were featured with abundant active edge sites, short ions diffusion distance and structural stability during electrochemical reactions. High specific capacities and outstanding stability were achieved for their anode applications, i.e., in LIBs ~820 and ~480 mA h g−1 at the current densities of 1 and 20 A g−1, respectively, and in SIBs ~520 and ~380 mA h g−1 at 1 and 20 A g−1 after 100 cycles, respectively. MoS2 NBs also exhibited decent performance in a wide temperature range from −20 °C to 60 °C, in particular as anodes in LIBs. Electrochemical kinetics analysis confirmed that the pseudocapacitive behavior had an over 90% contribution in the overall energy storage process of MoS2 NBs, which led to their excellent high-rate performance in both sodium and lithium storage.