Zn-doped MnO_x nanowires displaying plentiful crystalline defects and tunable small cross-sections for an optimized volcano-type performance towards supercapacitors

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Ribeiro, Geyse A. C. ; de Lima, Scarllett L. S. ; Santos, Karolinne E. R. ; Mendonca, Jhonatam P. ; Macena, Pedro ; Pessanha, Emanuel C. ; Cordeiro, Thallis C. ; Gardener, Jules ; Solorzano, Guilhermo ; Fonsaca, Jessica E. S. ; Domingues, Sergio H. ; dos Santos, Clenilton C. ; Dourado, Andre H. B. ; Tanaka, Auro A. ; da Silva, Anderson G. M. ; Garcia, Marco A. S.

• Tipo de documento: Artigo Científico
• Fonte: DISCOVER NANO; v. 18, n. 1, p. 16-pg., 2023-12-04.

Resumo

MnOx-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 MnOx 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 alpha-MnOx 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. (AU)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs