Asymmetric All‐Metal‐Oxide Supercapacitor with Superb Cycle Performance

Abstract

Metal oxides have great potential for developing high-performance supercapacitors due to their high specific capacitances. However, achieving high energy densities while maintaining good rate capability and long cycle life has proved to be challenging. We propose herein a strategy for constructing all-metal-oxide asymmetric supercapacitors (ASCs), in which both the cathode and anode are based on metal oxides, and demonstrate their outstanding electrochemical performance. We anchored SnO nanoparticles on the surface of reduced graphene oxide (RGO) through Sn-O-C bonds (as the cathode of ACSs), and employed low-crystalline RGO/MoO nanosheets as the anode, based on the large work function difference between SnO and MoO . The resulting ASC can operate stably at 1.8 V in neutral aqueous electrolyte and deliver an energy density of up to 33 W h kg , which remains at 13.8 W h kg even at 37.5 kW kg . Moreover, the ASC exhibits a good cycling stability of 92.5 % capacitance retention after 20 000 cycles.

Chemically Binding Scaffolded Anodes with 3D Graphene Architectures Realizing Fast and Stable Lithium Storage

“…The increased binding energy indicates a decreased electron density at Sn sites, and the positive shift can be attributed to the formation of Sn−O−C bonds between Sn–Ni alloy and graphene matrix since carbon has a higher electronegativity than that of tin [25]. The presence of Sn−O−C bonds is also confirmed by the O 1s and C 1s XPS spectra of the Sn–Ni/G dual framework () [26]. The strong interfacial Sn–O–C bonding not only prevents the detachment and aggregation of Sn–Ni alloy, but also accelerates charge transport between alloy scaffold and graphene matrix upon cycling [22–27].…”

Honeycomb LaMnO3 Perovskite Synthesized by a Carbon Sphere as a Self-Sacrificing Template for Supercapacitors

“…As the chemically active part of the supercapacitor, the electrode material determines the performance of the device to a large extent. At present, the electrode materials of supercapacitors are mainly divided into three categories: carbon materials, metal oxides/hydroxides, and metal sulfide and conductive polymers. − As metal oxides, perovskites with good conductivity, electrochemical activity, and long cycle life are widely used in electrochemical research, such as supercapacitors, electrochemical sensors, electrocatalytic materials, and so on. − …”

Diethanolamine-Assisted Preparation of Reed Flower-Derived Nitrogen-Doped Porous Carbon for Supercapacitor Electrodes

“…The properties of electrode materials are key in determining the energy storage capacity of supercapacitors, , and within this field, the development of nanostructured materials has become a research hotspot. Electrode materials of a supercapacitor mainly include metal oxides, − conductive polymer materials, − and carbon-based materials. − Carbon-based materials, including activated carbon, carbon nanotubes, templated carbon, carbon aerogel, and graphene, have the advantages of controllable porosity, good cycle stability, high conductivity, and high environmental compatibility. Among all carbon-based materials, biomass-derived porous activated carbon, as a kind of environmentally friendly material, attracts heightened attention due to the abundance of raw materials, easy procurement, low cost, large specific surface area, and superior electrochemical performance.…”