Effects of Microstructure on Electrode Properties of Nanosheet-Derived Hx(Ni1/3Co1/3Mn1/3)O2 for Electrochemical Capacitors

摘要

Nanosheet-derived Hx(Ni1/3Co1/3Mn1/3)O2 was prepared by restacking (Ni1/3Co1/3Mn1/3)O2 nanosheets with large or small lateral sizes and their electrochemical properties in a 1 M KOH aqueous solution; microstructural factors were compared with those of bulk Hx(Ni1/3Co1/3Mn1/3)O2 (HNCM). The electrodes composed of small nanosheets exhibited very large capacitances of 1241 F·g⁻¹ (395 mAh·g⁻¹) at a current density of 50 mA·g⁻¹, and 430 F·g⁻¹ (100 mAh·g⁻¹) at a large current density of 1000 mA·g⁻¹. These large capacitances resulted from a heterogeneous layer structure with a large surface area and pore volume. The electrodes of large nanosheets, with a strongly interconnected microstructure and a surface area slightly larger than that of HNCM, exhibited good cycle stability and capacitances larger than that of HNCM. Microstructural control through the restacking of (Ni1/3Co1/3Mn_1/3)O₂ nanosheets improved the electrochemical properties of H_x(Ni, Co, Mn)O₂.