WSe_2负载掺氮三维石墨烯的制备及储锂性能

The Preparation and Lithium Storage Properties of WSe_2 Nanorods Anchored on N-doped 3D Graphene

近年来,过渡金属硫族化合物由于具有较高的理论比容量及特殊的层状结构,被认为有希望替代石墨作为下一代锂离子电池负极材料.作为典型的过渡金属硫族化合物,硒化钨(WSe_2)具有与石墨类似的二维层状结构,层间通过较弱的范德华力结合,方便锂离子嵌入和脱嵌.然而,在实际应用中,导电性差、循环过程中体积膨胀等问题制约了其进一步的发展.为了解决以上问题,本文经水热、退火等步骤,制备了将纳米棒状WSe_2锚定在掺氮三维石墨烯上的WSe_2@N-3DG复合材料.电化学测试表明,电流密度为2 A·g^(-1)时,复合材料循环500圈后放电比容量可以达到412 m Ah·g^(-1),在0.1,0.2,0.5,1和2 A·g^(-1)的电流密度下,WSe_2@N-3DG的放电比容量分别达到811,696,576,443和391 mAh·g^(-1),表现出优异的电化学性能.

Due to their higher theoretical specific capacity and novel layered structures,transition-metal dichalcogenides（ TMDs） have been recently regarded as promising next generation high performance lithium ion battery（ LIB） electrode materials. Among them,WSe2 processes graphene-like layered structures with interaction by wake van der Waals forces,which is beneficial to fast insertion/deinsertion of Li＋ion. However,poor electrical conductivity as well as large volume changes during cycling severely limit its use for practical lithium ion battery. To address these issues,WSe2 nanorods anchored on N-doped three dimensional graphene hybrids（ WSe2@ N-3DG） have been successfully synthesized by a simple two-step process and their lithium storage performances were characterized in this work. The prepared WSe2@ N-3DG exhibited excellent electrochemical performances,i. e.,a reversible capacity of 412 m Ah·g^-1 after 500 cycles at 2A·g^-1 and delivered large capacities of 811,696,576,443 and 391 m Ah·g^-1 under current densities of 0. 1,0. 2,0. 5,1,2 A·g^-1.