Amorphous H0.82MoO3.26 cathodes based long cyclelife fiber-shaped Zn-ion battery for wearable sensors

Abstract

The conductivity and structural intrinsic stability of cathode materials are the barriers to achieve high-performance fiber-shaped Zn-ion batteries (FZIBs). Here, amorphous H0.82MoO3.26 coated on carbon nanotubes fiber (noted as CHMO) is exploited as cathode materials for aqueous FZIBs with high energy density, excellent cycle stability and good omnidirectional flexibility. The amorphous H0.82MoO3.26 improves electron transfer and accelerates electrochemical reaction kinetic, as well as effectively suppresses structural degradation during repeated charge/discharge process. Meanwhile, the electrochemical behaviors combined with a series of in-situ/ex-situ characterizations verify that Zn2+ and H+ ions insert/extract into/from the CHMO fiber reversibly at the same time. The assembled battery delivers high energy density of 32.1 mWh cm-3 (based on the volume of cathode) and excellent capacity retention of about 67% after 5000 cycles at 700 mA cm-3, as well as splendid flexibility (about 91% capacity retention after bending 3500 times). Wearable NO2 gas sensor and pressure sensor integrated with fiber-shaped Zn//CHMO battery are also fabricated, which can operate stably with stable signal output.