Pre‐intercalation of Ammonium Ions in Layered δ‐MnO2 Nanosheets for High‐Performance Aqueous Zinc‐Ion Batteries

Layered manganese dioxide is a promising cathode candidate for aqueous Zn‐ion batteries. However, the narrow interlayer spacing, inferior intrinsic electronic conductivity and poor structural stability still limit its practical application. Herein, we report a two‐step strategy to incorporate ammonium ions into manganese dioxide (named as AMO) nanosheets as a cathode for boosted Zn ion storage. K+‐intercalated δ‐MnO2 nanosheets (KMO) grown on carbon cloth are chosen as the self‐involved precursor. Of note, ammonium ions could replace K+ ions via a facile hydrothermal reaction to enlarge the lattice space and form hydrogen‐bond networks. Compared with KMO, the structural stability and the ion transfer kinetics of the layered AMO are enhanced. As expected, the obtained AMO cathode exhibits remarkable electrochemical properties in terms of high reversible capacity, decent rate performance and superior cycling stability over 10000 cycles. δ‐MnO2 nanosheets with intercalated ammonium ions (AMO) are synthesized via a self‐templated strategy as a Zn‐ion battery cathode. The incorporation of ammonium ions enlarges the interlayer space and forms hydrogen bonds for enhanced structural robustness and fast reaction kinetics. As a result, the AMO cathode exhibits exceptional rate performance and long lifespan in full cells.