Potassium-Ion Pillared Basic Copper Molybdate Nanoflowers as High-Performance Cathodes for Stable Aqueous...

This study addresses sluggish kinetics and limited cycling stability in aqueous ammonium-ion batteries (AAIBs) cathodes by synthesizing K⁺-, Ni²⁺-, and Mn²⁺-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 Ni²⁺ and Mn²⁺ 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.