Molybdophosphate derived MoP based electrocatalyst as cathode for Sn–H+ battery to generate H2 and electricity simultaneously

• Published in: Journal of solid state chemistry Vol. 277; pp. 602 - 610
• Main Authors: Wang, Lusha, Dong, Baichuan, Xu, Xinxin, Wang, Yi
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-09-2019
• Subjects: Electrocatalysis; HER; MoP; Polyoxometalates; Sn–H+ battery; Electrocatalysis; Polyoxometalates; HER; Sn–H+ battery; MoP
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2019.07.017

Sn–H+ battery is a new energy conversion equipment, which can produce H2 and electricity simultaneously. In this battery, the activity of hydrogen evolution reaction electrocatalyst on cathode plays an important role, which determines the performance of Sn–H+ battery greatly. Here, with highly reduced P4Mo6 type molybdophosphate as precursor, {Zn[Mo6O12(OH)3(HPO4)3(PO4)]2[Zn10(PO4)4(dpphen)6(H2O)8]}·6H2O (dpphen = 4,7-diphenyl-1,10-phenanthroline), an efficient MoP based electrocatalyst is synthesized. In this electrocatalyst, MoP particles about 30–50 nm disperse homogenously in mesoporous carbon carrier doped by phosphor and nitrogen. To obtain 10 and 100 mA cm−2 current in 0.5 M H2SO4, the electrocatalyst only requires 159 and 241 mV overpotential. During this process, Tafel slope is merely 70 mV·dec−1. The electrocatalyst keeps stable after multi-cycle and long time hydrogen evolution tests. With Sn slice as anode, this electrocatalyst as cathode active material, a Sn–H+ battery is constructed. Its open circuit voltage achieves 0.83 V with peak power density 53.5 mW cm−2. The voltage of Sn–H+ battery keeps constant for 5 h with discharge current density at 25 mA cm−2. During this process, the battery delivers specific capacity and power density of 370 mAh·g−1 and 188 Wh·kg−1. Besides electricity production, this battery can also generate H2. When discharge at 10 mA cm−2, its Faradic efficiency achieves 95.7%.
A versatile Sn-H+ battery is constructed successfully, which can generate electricity and H2 simultaneously with high efficiency. [Display omitted]
•MoP based electrocatalyst is synthesized without the usage of dangerous PH3.•This electrocatalyst exhibits excellent HER activity.•Sn–H+ battery is assembled with this electrocatalyst as cathode.•Sn–H+ battery can generate H2 and electricity simultaneously.