Tian Ye, Ma Yuxin, Sun Ruijin, Zhang Weichao, Liu Haikun, Liu Hao, Liao Libing
School of Science, China University of Geosciences, Beijing 100083, China.
Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China.
Nanomaterials (Basel). 2023 Apr 19;13(8):1411. doi: 10.3390/nano13081411.
Two-dimensional nanomaterials hold great promise as electrode materials for the construction of excellent electrochemical energy storage and transformation apparatuses. In the study, metallic layered cobalt sulfide was, firstly, applied to the area of energy storage as a supercapacitor electrode. By a facile and scalable method for cathodic electrochemical exfoliation, metallic layered cobalt sulfide bulk can be exfoliated into high-quality and few-layered nanosheets with size distributions in the micrometer scale range and thickness in the order of several nanometers. With a two-dimensional thin sheet structure of metallic cobalt sulfide nanosheets, not only was a larger active surface area created, but also, the insertion/extraction of ions in the procedure of charge and discharge were enhanced. The exfoliated cobalt sulfide was applied as a supercapacitor electrode with obvious improvement compared with the original sample, and the specific capacitance increased from 307 F∙g to 450 F∙g at the current density of 1 A∙g. The capacitance retention rate of exfoliated cobalt sulfide enlarged to 84.7% from the original 81.9% of unexfoliated samples while the current density multiplied by 5 times. Moreover, a button-type asymmetric supercapacitor assembled using exfoliated cobalt sulfide as the positive electrode exhibits a maximum specific energy of 9.4 Wh∙kg at the specific power of 1520 W∙kg.
二维纳米材料作为构建优异电化学储能和转换装置的电极材料具有巨大潜力。在该研究中，金属层状硫化钴首先被用作超级电容器电极应用于储能领域。通过一种简便且可扩展的阴极电化学剥离方法，金属层状硫化钴块体可被剥离成高质量的少层纳米片，其尺寸分布在微米尺度范围内，厚度约为几纳米。金属钴硫化物纳米片的二维薄片结构不仅创造了更大的活性表面积，而且还增强了充放电过程中离子的插入/脱出。与原始样品相比，剥离后的硫化钴用作超级电容器电极有明显改善，在1 A∙g的电流密度下，比电容从307 F∙g增加到450 F∙g。当电流密度乘以5倍时，剥离后的硫化钴电容保持率从未剥离样品的81.9%扩大到84.7%。此外，以剥离后的硫化钴为正极组装的纽扣型不对称超级电容器在1520 W∙kg的比功率下表现出9.4 Wh∙kg的最大比能量。
