Jeong Sun Young, Cho Jung Sang
Department of Engineering Chemistry, Chungbuk National University, Chungbuk 361-763, Korea.
Nanomaterials (Basel). 2019 Sep 23;9(10):1362. doi: 10.3390/nano9101362.
Well-designed porous structured bimetallic ZnSe/CoSe₂/carbon composite nanofibers with uniformly distributed pores were prepared as anodes for sodium-ion batteries by electrospinning and subsequent simple heat-treatment processes. Size-controlled polystyrene (PS) nanobeads in the electrospinning solution played a key role in the formation and uniform distribution of pores in the nanofiber structure, after the removal of selected PS nanobeads during the heat-treatment process. The porous ZnSe/CoSe₂/C composite nanofibers were able to release severe mechanical stress/strain during discharge-charge cycles, introduce larger contact area between the active materials and the electrolyte, and provide more active sites during cycling. The discharge capacity of porous ZnSe/CoSe/C composite nanofibers at the 10,000th cycle was 297 mA h g, and the capacity retention measured from the second cycle was 81%. The final rate capacities of porous ZnSe/CoSe/C composite nanofibers were 438, 377, 367, 348, 335, 323, and 303 mA h g at current densities of 0.1, 0.5, 1, 3, 5, 7, and 10 A g, respectively. At the higher current densities of 10, 20, and 30 A g, the final rate capacities were 310, 222, and 141 mA h g, respectively.
通过静电纺丝和随后的简单热处理工艺，制备了具有均匀分布孔隙的设计良好的多孔结构双金属ZnSe/CoSe₂/碳复合纳米纤维，用作钠离子电池的阳极。静电纺丝溶液中尺寸可控的聚苯乙烯（PS）纳米珠在热处理过程中去除选定的PS纳米珠后，对纳米纤维结构中孔隙的形成和均匀分布起到了关键作用。多孔ZnSe/CoSe₂/C复合纳米纤维在充放电循环过程中能够释放严重的机械应力/应变，在活性材料和电解质之间引入更大的接触面积，并在循环过程中提供更多的活性位点。多孔ZnSe/CoSe/C复合纳米纤维在第10000次循环时的放电容量为297 mA h g，从第二次循环开始测量的容量保持率为81%。多孔ZnSe/CoSe/C复合纳米纤维在电流密度分别为0.1、0.5、1、3、5、7和10 A g时的最终倍率容量分别为438、377、367、348、335、323和303 mA h g。在10、20和30 A g的较高电流密度下，最终倍率容量分别为310、222和141 mA h g。
