Search

To improve the electrochemical performance of supercapacitors, pseudocapacitive electrode materials must be synthesized with high surface activity, high electrical conductivity, and ultralong cycle life, which presents a significant challenge. In this study, we reported on the synthesis of sulfur-vacancy-enriched sheet-like Ni 3 S 2 @ZnS composites based on 3D network porous nickel foam (NF) using a two-step electrodeposition protocol. The Ni 3 S 2 @ZnS/NF exhibited a specific capacitance of 1141.9 C g−1 (241.0 mC cm−2) at a current density of 19 A g−1 (5 mA cm−2). The Ni 3 S 2 @ZnS/NF positive electrode was used to fabricate an all-solid asymmetric supercapacitor, which demonstrated an ultrahigh energy density of 12.0 μWh cm−2 at a power density of 7.2 mW cm−2, as well as an ultrahigh capacitance retention rate of 86.7% after 50,000 cycles. Experimental and theoretical results indicated that the introduction of sulfur vacancies could improve the surface activity of the electrode, as well as its hydroxide diffusion and adsorption ability by adjusting the surrounding local electron concentration of cations around them. This accelerated the interfacial redox reaction and resulted in remarkable electrochemical performance for the Ni 3 S 2 @ZnS/NF electrode. This research provides a pathway for the controlled synthesis of 2D nanosheets with vacancy-rich structures and their potential electrochemical applications. • The sulfur-vacancy-enriched sheet-like Ni 3 S 2 @ZnS composite has been conceived. • Abundant sulfur vacancies make the material have high capacitive properties. • The theoretical studies further deepen structure-activity relationship of sulfur vacancies. • An ultrahigh capacitance retention supercapacitor is fabricated. [ABSTRACT FROM AUTHOR]

Solid-state electrolytes have become a promising approach for rechargeable lithium batteries with enhanced safety and high energy density. However, the rigid nature of ceramic electrolytes would result in the poor interfacial contact, and polymer electrolytes suffer from inferior electrochemical performance and unsatisfied mechanical strength to suppress Li dendrites. In this work, we report a flexible Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP)-reinforced polyvinylidene fluoride (PVDF)-based solid composite electrolyte with superior performances in terms of high ionic conductivity (1.64 × 10−3 S cm−1 at room temperature), high lithium transference number (0.45), wide electrochemical window (0–4.76 V) and enhanced tensile strength (14.2 MPa). The existence of LATP permits the utilization of high Li-salt content which increases the charge carrier concentration. Meanwhile, LATP facilitates the Li+ conduction process and enhances the mechanical strength, leading to a long-term electrochemical stability of symmetric Li cell for 600 h at 0.2 mA cm−2. Assembled with LiFePO 4 cathode, the all-solid-state Li battery delivers a high capacity of 153.7 mA h g−1 at 0.3 C with remarkable cycle stability. This work provides a bright future for composite polymer electrolytes in the application of all-solid-state lithium batteries. • A LATP-reinforced PVDF-based solid-state composite electrolyte was prepared. • The existence of LATP permits the utilization of high Li-salt content. • A long-term electrochemical stability of the Li symmetric cell was achieved. • LiFePO 4 | CPE |Li battery delivers excellent cycle stability at room temperature. [ABSTRACT FROM AUTHOR]