Hierarchical FexBi2−xS3 solid solutions for boosted supercapacitor performance
Fengming Zhou, Xiaodong Wang, Ruijie Jing, Xiaoyu Li, Qi Zhang, Zhenjiang Li, Yunmei Du, Zhenyu Xiao, Lei Wang
Abstract
For the pursuit of high energy supercapacitors, the development of high performance pseudocapacitance or battery-type negative electrode material is urgently needed to make up for the capacity shortage of commercial electric double layer capacitor (EDLC) type materials. Herein, a porous and defect-rich Fe x Bi 2− x S 3 solid solution structure is firstly constructed by employing Fe-doped Bi 2 O 2 CO 3 porous nanosheets as a precursor, which presents dramatically increased energy storage performance than Bi 2 S 3 and FeS 2 phase. For the optimized Fe x Bi 2− x S 3 solid solution (FeBiS-60%), the Fe solute is free and random dispersed in Bi 2 S 3 framework, which can effectively modulate the electronic structure of Bi element and introduce rich-defect due to the existence of Fe(II). Meanwhile, the FeBiS-60%, constructed by pore nanosheets that are assembled by self-supported basic nanorod units, presents rich mesoporous channels for fast mass transfer and abundant active sites for promoting capacity performance. Therefore, a high capacitance of 832.8 F·g −1 at a current density of 1 A·g −1 is achieved by the FeBiS-60% electrode. Furthermore, a fabricated Ni 3 S 2 @Co 3 S 4 (NCS)//FeBiS-60% hybrid supercapacitor device delivers an outstanding energy density of 85.33 Wh·kg −1 at the power density of 0.799 kW·kg −1 , and ultra-long lifespan of remaining 86.7% initial capacitance after 8700 cycles.