Mo3Sn-modified Bi2W2O9 hybrid heterostructure as a high-performance electrode material for supercapacitors

A key challenge for advanced supercapacitors is the development of high-performance electrode materials that can achieve fast charge transport and a large number of electroactive sites. In this work, a new Mo 3 Sn@Bi 2 W 2 O 9 hybrid is synthesized by hydrothermal process to promote the electrochemical properties of Bi 2 W 2 O 9 by heterostructure engineering. Based on structural characterization, one can conclude that the Mo 3 Sn and Bi 2 W 2 O 9 phases are coexisting in the hybrid, with an average crystallite size of 41.3 nm for pristine Bi 2 W 2 O 9 reduced to 25.3 nm for the hybrid. EDX and elemental mapping of the heterostructure show that it is uniformly distributed in the sample, and the BET analysis reveals that the structure has a larger specific surface area (61.5 to 69.2 m 2 g -1 ), which create more electrochemically active sites and allows for more diffusion of electrolyte ions. The Mo 3 Sn@Bi 2 W 2 O 9 electrode exhibits a high specific capacitance of 411.4 F g -1 at 1 A g -1 , about 3.8 times as high as that of pristine Bi 2 W 2 O 9 (107 F g -1 ). Moreover, the hybrid electrode also shows decreased charge-transfer resistance and improved ion diffusion, which again indicates the fast electron transfer at the heterointerface. The excellent electrochemical properties are due to the synergy between conductive Mo 3 Sn and Bi 2 W 2 O 9 which enhances electrical conductivity, exposes more active sites, and accelerates faradaic reactions. The results show that the Mo 3 Sn@Bi 2 W 2 O 9 hybrid could be used as a promising electrode material for next-generation high-performance supercapacitors.