SnS2纳米花/石墨烯纳米复合物的一步法合成及其增强的锂离子存储性能

摘要

SnS2 is considered as an attractive anode material to substitute commercial graphite anodes of lithium-ion batteries due to its high specific capacity of 645 mAh·g-1 as well as low cost.Nevertheless,it suffers poor large volume expansion during the lithiation/delithiation processes,leading to the loss of electrical contact and rapid capacity fading.Herein,by using a facile one-step solvothermal method,SnS2 nanoflower/graphene nanocomposites (SnS2 NF/GNs) were prepared,where flower-like SnS2 hierarchical nanostructures consisting of ultrathin nanoplates,are tightly enwrapped in graphene nanosheets.As anode materials for lithium-ion batteries,the SnS2 NF/GNs electrode exhibit superior electrochemical performance,with a reversible capacity of 523 mAh·g-1 after 200 charge-discharge cycles.The enhanced Li storage performance was attributed to the synergistic effect of SnS2 and graphene.The SnS2 NF can effectively accommodate the volume change and shorten Li+ diffusion distance,while graphene nanosheets can further alleviate the volume expansion of SnS2 and improve the electronic conductivity.%SnS2由于具有较高的储锂容量(645 mAh·g-1)、价格低廉等优点而受到研究者的广泛关注.但纯SnS2在脱嵌锂过程中存在严重的体积膨胀效应,造成活性物质粉化和剥落,从而导致容量的迅速衰减.针对这一问题,本文采用简单的一步溶剂热法制备了SnS2纳米花/石墨烯(SnS2 NF/GNs)纳米复合物.其中花状SnS2由超薄纳米片组装而成,石墨烯纳米片将SnS2包裹在其中.将该材料用作锂离子电池负极时,SnS2 NF/GNs表现出优越的电化学性能,如:循环200圈后可逆容量仍可达523 mAh·g-1复合物材料提高的储锂性能得益于SnS2和石墨烯的协同效应.纳米结构的SnS2可以有效的缓冲体积的膨胀,缩短锂离子的扩散距离.石墨烯纳米片不仅可以进一步缓冲SnS2体积的膨胀,而且可以提高纳米复合物的导电性.