Potassium‐Ion Pillared Basic Copper Molybdate Nanoflowers as High‐Performance Cathodes for Stable Aqueous Ammonium‐Ion Batteries

This study addresses sluggish kinetics and limited cycling stability in aqueous ammonium‐ion batteries (AAIBs) cathodes by synthesizing K ⁺ ‐, Ni ²⁺ ‐, and Mn ²⁺ ‐doped basic copper molybdate (CuMoO) via a hydrothermal route. Systematic characterization demonstrates that K ⁺ incorporation markedly expands interlayer spacing, enhances electronic conductivity, and reinforces structural integrity, surpassing the effects of Ni ²⁺ and Mn ²⁺ substitution. The optimally doped sample (CuMoO‐K‐0.6) exhibits a flower‐like micro‐nanoarchitecture assembled from one‐dimensional nanorods, featuring high crystallinity and uniform elemental dispersion. Electrochemically, it displays minimal charge‐transfer resistance (0.7 Ω) and a pseudocapacitive contribution of 92.7%. A specific discharge capacity of 319.8 mAh g ⁻¹ is achieved at 0.1 A g ⁻¹ , with 98.8% retention after 100 cycles. Notably, 82.9% capacity is retained following 1000 cycles at 1.0 A g ⁻¹ , confirming excellent specific capacity, rate capability, and long‐term durability. This work elucidates the structure–activity correlation and enhancement mechanism induced by K ⁺ doping, thereby furnishing experimental evidence and a theoretical foundation for the rational design of advanced AAIBs cathodes.