碳修饰的HMCS@ReS_(2)的合成及其储钠性能研究

Synthesis and sodium storage properties of HMCS@ReS_(2)with carbon modification

二硫化铼(ReS_(2))作为过渡金属二硫化物的一员,由于极弱的层间范德华相互作用、较弱的层间耦合能量和较大的层间距,在钠离子电池领域有着良好的应用前景。但是ReS_(2)自身较低的本征电导率和充放电过程中较大的体积膨胀严重限制了其电化学储钠能力。在空心介孔碳球(HMCS)上原位生长ReS_(2)纳米片(HMCS@ReS_(2)),将HMCS@ReS_(2)复合材料作为高性能钠离子电池负极。碳基材料的复合弥补了ReS_(2)电导率不足的缺陷,促进了电子的快速转移;空心介孔碳球为ReS_(2)的体积变化提供了足够的缓冲空间,维持了电极材料的结构稳定性。HMCS@ReS_(2)作为钠离子电池负极材料时有着优异的倍率性能和循环性能。结果表明,HMCS@ReS_(2)电极在0.2,0.5,1.0,2.0,5.0 A·g^(-1)的电流密度下分别表现出388.5,343.4,305.3,262.4,180.1 mAh·g^(-1)的放电比容量。在2.0 A·g^(-1)电流密度下循环3000次后比容量保持在65 mAh·g^(-1),平均每圈的容量衰减率仅为0.074%。

As a member of transition metal disulfides,rhenium disulfide(ReS_(2))has promising applications in the sodium ion batteries due to its extremely weak interlayer Van der Waals interactions,weak interlayer coupling energy and large layer spacing.However,the low intrinsic conductivity of ReS_(2)and the large volume expansion during charging and discharging severely limit its electrochemical sodium storage capacity.In this work,ReS_(2)nanosheets were in situ grown on the hollow mesoporous carbon spheres(HMCS),and the resulting HMCS@ReS_(2)composites were used as the anode of high-performance sodium ion batteries.The deficiency of ReS_(2)conductivity was compensated by the composite of carbon-based material and the rapid electron transfer was promoted.HMCS provides enough buffer space for the volume change of ReS_(2)and the structural stability of the electrode material was maintained.HMCS@ReS_(2)exhibited excellent rate performance and cycling performance when used as the anode material for sodium ion batteries.The discharge capacities of 388.5,343.4,305.3,262.4,and 180.1 mAh·g^(-1)at current densities of 0.2,0.5,1.0,2.0,and 5.0 A·g^(-1)was demonstrated.The HMCS@ReS_(2)electrode could operate for 3000 cycles at a current density of 2.0 A·g^(-1),and a capacity of 65 mAh·g^(-1)with an average capacity decay rate of only 0.074%per cycle was achieved.