Peng Huifen, Wang Xiaoran, Zhao Yan, Tan Taizhe, Bakenov Zhumabay, Zhang Yongguang
School of Materials Science & Engineering, Research Institute for Energy Equipment Materials, Hebei University of Technology, Tianjin 300130, China.
Synergy Innovation Institute of GDUT, Heyuan 517000, China.
Polymers (Basel). 2018 Apr 3;10(4):399. doi: 10.3390/polym10040399.
Rechargeable lithium/sulfur (Li/S) batteries have received quite significant attention over the years because of their high theoretical specific capacity (1672 mAh·g) and energy density (2600 mAh·g) which has led to more efforts for improvement in their electrochemical performance. Herein, the synthesis of a flexible freestanding sulfur/polyacrylonitrile/graphene oxide (S/PAN/GO) as the cathode for Li/S batteries by simple method via vacuum filtration is reported. The S/PAN/GO hybrid binder-free electrode is considered as one of the most promising cathodes for Li/S batteries. Graphene oxide (GO) slice structure provides effective ion conductivity channels and increases structural stability of the ternary system, resulting in excellent electrochemical properties of the freestanding S/PAN/GO cathode. Additionally, graphene oxide (GO) membrane was able to minimize the polysulfides' dissolution and their shuttle, which was attributed to the electrostatic interactions between the negatively-charged species and the oxygen functional groups on GO. Furthermore, these oxygen-containing functional groups including carboxyl, epoxide and hydroxyl groups provide active sites for coordination with inorganic materials (such as sulfur). It exhibits the initial reversible specific capacity of 1379 mAh·g at a constant current rate of 0.2 C and maintains 1205 mAh·g over 100 cycles (87% retention). In addition, the freestanding S/PAN/GO cathode displays excellent coulombic efficiency (100%) and rate capability, delivering up to 685 mAh·g capacity at 2 C.
多年来，可充电锂/硫（Li/S）电池因其高理论比容量（1672 mAh·g）和能量密度（2600 mAh·g）而备受关注，这促使人们为改善其电化学性能付出了更多努力。在此，报道了通过真空过滤的简单方法合成一种柔性自支撑硫/聚丙烯腈/氧化石墨烯（S/PAN/GO）作为Li/S电池的阴极。S/PAN/GO混合无粘结剂电极被认为是Li/S电池最有前景的阴极之一。氧化石墨烯（GO）的片状结构提供了有效的离子传导通道，并增加了三元体系的结构稳定性，从而使自支撑S/PAN/GO阴极具有优异的电化学性能。此外，氧化石墨烯（GO）膜能够最大限度地减少多硫化物的溶解及其穿梭效应，这归因于带负电的物质与GO上的氧官能团之间的静电相互作用。此外，这些含氧官能团，包括羧基、环氧基和羟基，为与无机材料（如硫）配位提供了活性位点。在0.2 C的恒定电流速率下，它表现出1379 mAh·g的初始可逆比容量，并在100次循环中保持1205 mAh·g（保留率约87%）。此外，自支撑S/PAN/GO阴极显示出优异的库仑效率（约100%）和倍率性能，在2 C时可提供高达685 mAh·g的容量。
