Quasi-Solid-State Flexible Zn–Air Batteries with a Hydrophilic-Treated Co@NCNTs Array Electrocatalyst and PEO–PANa Electrolyte

Abstract

In this work, we report an efficient and stable electrocatalyst (MoS2–Co@NCNTs) with a dense layer of MoS2 nanosheets compounded on the surface of Co@NCNTs. When tested in an oxygen-saturated electrolyte, MoS2–Co@NCNTs undergoes electrochemical reconfiguration (MoS2–Co@NCNTs–ER) and the MoS2 nanosheets are oxidized, resulting in some high-valence molybdenum–oxygen compounds (MoOx). The oxidized MoS2–ER nanoparticles significantly enhanced the hydrophilicity of the Co@NCNTs. Hydrophilicity improvement increased the electrochemical active surface area (ECSA) of MoS2–Co@NCNTs–ER and promoted the ion transport between the catalyst and electrolyte, which led to the enhanced OER/ORR catalytic performance compared with Co@NCNTs. Meanwhile, a PEO–PANa GPE with high electrical conductivity and excellent electrolyte absorption and retention capacity was reported. QSS-F-ZABs assembled with MoS2–Co@NCNTs and PEO–PANa GPE exhibit enhanced charge/discharge performance and long-cycle stability with a stable cycle of 200 h at a current density of 2 mA cm–2 and 160 h at a current density of 5 mA cm–2.