MXene-Carbon Fiber Composite as Anode Protector for Zn-Ion Batteries for Dendrite Suppression

Aqueous Zn-ion batteries (AZIBs) are recognized as highly promising energy storage solutions for sustainable and future grid-scale applications. However, their practical deployment in the industry is hindered by parasitic reactions with dendrite growth being a primary issue. This study introduces an original approach using MXene-coated carbon fiber as an anode protector to mitigate dendrite formation, thereby enhancing battery longevity and stability. The method involves wrapping carbon fibers with thin MXene sheets, approximately 30 nm thick, to create a protective layer. This MXene coating is selected for its high Zn affinity, reduced nucleation and plating overpotential, anticorrosive properties, and improved diffusion kinetics for Zn-ion migration. These characteristics significantly extend the lifespan of symmetrical cell anodes, achieving up to 1150 h of stable operation at 1 mA cm–2/1 mAh cm–2. Additionally, when applied to full cells paired with V2O5 as the cathode, the MXene-coated carbon fiber anode protector demonstrates remarkable longevity and cycling performance, supporting up to 1000 cycles with capacitiy up to 260 mAh g–1 at 0.25 A g–1. This strategy effectively suppresses major parasitic reactions, thereby increasing both the lifetime and the performance of batteries.