A Hyperstable Aqueous Zinc-Ion Battery Based on Mo1.74CTz MXene.

Abstract

The sustainable utilization of natural resources and growing demand for various electronic devices have promoted the development of safe, stable, and rechargeable aqueous zinc-ion batteries (AZIBs). However, a stable cathode material is crucial for ZIBs in an aqueous electrolyte, since it is more difficult for divalent Zn²⁺ to be reversibly inserted and extracted between active materials than it is for monovalent metal ions. In this work, a tailored multi-defect MXene, Mo_1.74CT_z, of a complete chemical formula of Mo_1.74±0.06CO_0.95±0.02(OH)_0.63±0.01F_0.3±0.03.0.2±0.05H₂O_ads (Mo_1.74CT_z), is assembled as cathode in AZIBs. It achieved 75% capacity retention and nearly 100% Coulombic efficiency even after up to 100 000 cycles as the intrinsic structural stability and many vertical holes of the Mo_1.74CT_z MXene contributed to alleviating the MXene collapse under repeated charge and discharge. Meanwhile, the Mo_1.74CT_z-based AZIBs exhibited good performance with a specific capacity of 200 mAh g^-1 at a current density of 0.2 A g^-1, which greatly exceeds previous reports of pure MXene-based cathodes in AZIBs. This work will aid in finding new solutions for sustainable energy development, which will pave the way for AZIBs as an alternative to lithium-ion batteries (LIBs) in the future.