3D-Confined Zn Storage via Nitrogen-Doped Bamboo-Derived Hard Carbon Enables Stable and Kinetically Enhanced Zn Anodes.

Aqueous zinc-ion batteries (AZIBs) hold great promise for large-scale energy storage, yet their practical application is hindered by Zn dendrites, interfacial corrosion, and sluggish Zn2+ transportation. Herein, we propose a novel 3D confined zinc storage strategy by constructing a nitrogen-doped hard carbon (N-BHC) coating on the Zn anode. The N-BHC features abundant closed pores and uniformly distributed pyridinic N sites, enabling multisynergistic regulation. Specifically, its framework acts as a physical barrier to isolate Zn from electrolytes, suppressing hydrogen evolution and corrosion. The closed pores are suggested to act as localized Zn2+ storage reservoirs to homogenize electric field distribution, thereby inhibiting dendrite formation. Moreover, pyridinic N sites enhance ion conductivity, accelerating Zn2+ transport kinetics. Benefiting from these merits, the N-BHC@Zn anode exhibits exceptional cycling stability (over 2500 h at 1 mA cm-2/1 mAh cm-2), ultralow polarization (∼18 mV) and superior rate capability even at 5 mA cm-2. Furthermore, the N-BHC@Zn//MnO2 full cell delivers a specific capacity above 200 mAh g-1 at 1 A g-1 even after 1200 cycles. This work establishes a new paradigm for regulating ion transport and stabilizing electrode-electrolyte interfaces through rational pore structure engineering. This strategy can be readily extended to other aqueous metal-ion batteries that exhibit similar dendrite and corrosion issues.