High-Entropy MXene Inks for Light-Induced Sintering of Flexible Zn-Air Batteries

The FlexZAB proposal introduces an innovative approach to producing a new generation of printed flexible Zn-air batteries (ZABs), addressing key challenges such as sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics and high overpotential in traditional ZABs, while preserving the integrity of the support structure without traditional high-temperature sintering during manufacturing. The central component of this approach in FlexZAB is the synthesis and use of high-entropy MXenes (HEMXs), which play a pivotal role in both the fabrication process and the improved performance of the ZAB.MXenes, a family of two-dimensional (2D) carbides and nitrides of transition metals, are highly regarded for their flexibility, superior electrical conductivity, and partially metallic properties. Their 2D morphology makes them ideal for flexible applications, and they exhibit plasmonic effects under light irradiation, akin to Au and Ag. Incorporating multiple transition metals at the M site in HEMXs introduces a nearly infinite range of tunable compositions and properties. This leads to a quasi-continuous density of electronic surface states, promoting complex and reversible catalytic reactions such as ORR and OER.During flexible ZAB fabrication process of FlexZAB, the plasmonic properties of HEMXs will facilitate light-triggered sintering during manufacturing. The flexibility and interconnect of HEMXs serve as binders, enabling the production of additive-free inks and cathodes through aerosol direct-write printing. In battery operation, HEMXs boost performance by enhancing charge transport through high electrical conductivity. Additionally, their compositional versatility and abundant surface adsorption/reaction sites catalytically accelerate ORR and OER, resulting in more efficient battery performance.