Flexible and Free-Standing Ti₃C₂T_<i>x</i> MXene@Zn Paper for Dendrite-Free Aqueous Zinc Metal Batteries and Nonaqueous Lithium Metal Batteries

Abstract

Dendrite growth of metal anodes is one of the key hindrances for both secondary aqueous metal batteries and nonaqueous metal batteries. In this work, a freestanding Ti₃C₂T_<i>x</i> MXene@Zn paper is designed as both zinc metal anode and lithium metal anode host to address the issue. The binder-free Ti₃C₂T_<i>x</i> MXene@Zn paper exhibits merits of good mechanical flexibility, high electronic conductivity, hydrophilicity, and lithiophilicity. The crystal growth mechanism of Zn metal on common Zn foil and Ti₃C₂T_<i>x</i> MXene@Zn composite is also studied. It is found that the Ti₃C₂T_<i>x</i> MXene@Zn paper can effectively suppress the dendrite growth of Zn, enabling reversible and fast Zn plating/stripping kinetics in an aqueous electrolyte. Moreover, the Ti₃C₂T_<i>x</i> MXene@Zn paper can be used as a 3D host for a lithium metal anode. In this host, Zn is utilized as a nucleation agent to suppress the Li dendrite growth. The freestanding Ti₃C₂T_<i>x</i> MXene@Zn@Li anode exhibits superior reversibility with high Coulombic efficiency (97.69% over 600 cycles at 1.0 mA cm^-2) and low polarization compared with the Cu@Li anode. These findings may be useful for the design of dendrite-free metal-based energy storage systems.