One-Step Synthesis of Co(OH)2/SnOᵪ/C Hybrid Nanosheets for Asymmetric Solid-State Supercapacitors

Abstract Material defects play an important role in metal oxide-based or hydroxide-based supercapacitors. Oxygen vacancies as anion vacancy defects can not only offer a high electron conductivity by act as shallow donors but also can adjust the materials’ surface properties. Herein, we synthesis a novel oxygen-vacancy-rich Co(OH)2/SnOᵪ/C hybrid nanosheets which are prepared by using a facile one-step hydrothermal route. Possessing special petal-like nanosheets and rich oxygen vacancies, the as-prepared dual ligand hybrid nanosheets (marked Co(OH)2/SnOᵪ/C) present a high specific capacitance of 806.36 F g−1 at 1 A g−1, much higher than single ligand compound (338.36 F g−1 or 450.00 F g−1). The solid-state asymmetrical supercapacitors assembled with Co(OH)2/SnOᵪ/C show energy density of 49.73 Wh kg−1 with a power density of 1599.98 W kg−1, and good cycle stability with 64.43% capacitance retention after 20,000 cycles at the current density of 1 A g−1.