Utilizing Cationic Vacancies and Spontaneous Polarization on Cathode to Enhance Zinc‐Ion Storage and Inhibit Dendrite Growth in Zinc‐Ion Batteries

High energy density and intrinsic safety are the central pursuits in developing rechargeable Zinc‐ion batteries (ZIBs). The capacity and stability of nickel cobalt oxide (NCO) cathode are unsatisfactory because of its semiconductor character. Herein, we propose a built‐in electric field (BEF) approach by synergizing cationic vacancies and ferroelectric spontaneous polarization on cathode side to facilitate electron adsorption and suppress zinc dendrite growth on the anode side. Concretely, NCO with cationic vacancies was constructed to expand lattice spacing for enhanced zinc‐ion storage. Heterojunction with BEF leads to the Heterojunction//Zn cell exhibiting a capacity of 170.3 mAh g−1 at 400 mA g−1 and delivering a competitive capacity retention of 83.3 % over 3000 cycles at 2 A g−1. We conclude the role of spontaneous polarization in suppressing zinc dendrite growth dynamics, which is conducive to developing high‐capacity and high‐safety batteries via tailoring defective materials with ferroelectric polarization on the cathode. Cationic vacancies of nickel cobalt oxide (NCOV) and a built‐in electric field (BEF) at the heterojunction cathode are introduced to boost zinc‐ion adsorption and transport in Zn‐ion batteries. The growth of zinc dendrites is inhibited by a mitigating electrolyte concentration gradient resulting from the ferroelectric spontaneous polarization field (SPF). Consequently, the NCOV/BFO heterojunction//Zn cell exhibits a comparable specific capacity and delivers a competitive capacity retention of 83.3 % over 3000 cycles.