TiO2-x@MXenes with highly exposed (001) crystal facet and overlap orbitals for ultra-stable and kinetics-enhanced aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are ideal candidates for advanced energy storage systems because of their safety, budget-friendliness, and environmental sustainability. However, parasitic hydrogen evolution reactions (HERs) and uncontrolled Zn dendrite growth severely limit their application. To tackle these challenges, we design a protective layer comprising TiO 2-x nanosheets with highly exposed (001) crystal facet anchored on Ti-defective Ti 3 C 2 T x MXene (T(001)@MX)—a rarely achieved configuration for Zn anode stabilization. The overlap of Ti 3d and O 2p orbitals between T(001) and MX components in T(001)@MX modulates d-band center, while the built-in electric field promotes charge transfer from MX to T(001), creating a synergistic electronic compensation effect. This design, coupled with the zincophilic TiO 2 (001) crystal facet, ensures uniform electric field distribution, reduces Zn 2+ nucleation barrier, accelerates charge transport, and suppresses HERs. Consequently, T(001)@MX/Zn symmetrical cell achieves an ultra-long cycling lifespan of 5200 h. Moreover, the T(001)@MX/Zn||V 2 O 5 full cell exhibits a high specific capacity of 236.2 mAh g −1 and retains 78.2% after 5000 cycles at 10 A g −1 , outperforming all reported similar Zn||V-based full cells. This work introduces an innovative strategy to stabilize Zn anodes, offering a pathway toward high-performance, scalable, and durable energy storage technologies. An advanced artificial protective layer comprising TiO 2-x nanosheets with highly exposed (001) crystal facet anchored on Ti 3 C 2 T x MXene layers (T(001)@MX) ensures uniform electric field distribution, reduces Zn 2+ nucleation barrier, accelerates Zn 2+ /charge transport, and suppresses HER. • TiO 2-x with highly exposed (001) crystal facet anchored on MXene (T(001)@MX) as novel protective layer was constructed. • Surface properties of T(001)@MX protective layer were explored by theoretical calculations and COMSOL multiphysics simulation. • The T(001)@MX/Zn||V 2 O 5 full cell delivers exceptional capacity (236.2 mAh g −1 ) and long cycle life (5000 cycles).