Zn‐doped MnO(x) nanowires displaying plentiful crystalline defects and tunable small cross-sections for an optimized volcano-type performance towards supercapacitors

MnO(x)-based nanomaterials are promising large-scale electrochemical energy storage devices due to their high specific capacity, low toxicity, and low cost. However, their slow diffusion kinetics is still challenging, restricting practical applications. Here, a one-pot and straightforward method was reported to produce Zn-doped MnO(x) nanowires with abundant defects and tunable small cross-sections, exhibiting an outstanding specific capacitance. More specifically, based on a facile hydrothermal strategy, zinc sites could be uniformly dispersed in the α-MnO(x) nanowires structure as a function of composition (0.3, 2.1, 4.3, and 7.6 wt.% Zn). Such a process avoided the formation of different crystalline phases during the synthesis. The reproducible method afforded uniform nanowires, in which the size of cross-sections decreased with the increase of Zn composition. Surprisingly, we found a volcano-type relationship between the storage performance and the Zn loading. In this case, we demonstrated that the highest performance material could be achieved by incorporating 2.1 wt.% Zn, exhibiting a remarkable specific capacitance of 1082.2 F.g(−1) at a charge/discharge current density of 1.0 A g(−1) in a 2.0 mol L(−1) KOH electrolyte. The optimized material also afforded improved results for hybrid supercapacitors. Thus, the results presented herein shed new insights into preparing defective and controlled nanomaterials by a simple one-step method for energy storage applications. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s11671-023-03933-2.