Zn-ion hybrid supercapacitors (ZHSs) are an advanced energy storage system with high energy/power density. However, the development of cathodes with high-performance is still a challenge. Herein, N, O co-doped hierarchical porous carbon (HPC) integrated with carbon cloth (CC) was fabricated as a promising cathode for aqueous ZHSs, which delivered a high specific capacity of 138.5 mA h g⁻¹ with excellent rate performance ( 75 mA h g⁻¹ at 20 A g⁻¹) and superb cycling stability without decay after 10 000 cycles. As a result, an exceptionally high energy density of 110 W h kg⁻¹ and attractive power density of 20 kW kg⁻¹ can be obtained. More importantly, the dual cation (H⁺ and Zn²⁺) chemical absorption process for additional capacity is firstly proposed and verified by ex situ experiments, while the precipitation/dissolution process of zinc hydroxide sulphate hydrate is explained. Furthermore, a quasi-solid-state HPC/CC-based ZHS device based on gel electrolyte also showed promising potential for practical applications. This work provides a new pathway to develop carbon-based cathode materials for sustainable ZHSs.

Graphene or graphene-like nanosheets have been emerging as an attractive reinforcement for composites due to their unique mechanical and electrical properties as well as their fascinating two-dimensional structure. It is a great challenge to efficiently and homogeneously disperse them within a metal matrix for achieving metal matrix composites with excellent mechanical and physical performance. In this work, we have developed an innovative in situ processing strategy for the fabrication of metal matrix composites reinforced with a discontinuous 3D graphene-like network (3D GN). The processing route involves the in situ synthesis of the encapsulation structure of 3D GN powders tightly anchored with Cu nanoparticles (NPs) (3D GN@Cu) to ensure mixing at the molecular level between graphene-like nanosheets and metal, coating of Cu on the 3D GN@Cu (3D GN@Cu@Cu), and consolidation of the 3D GN@Cu@Cu powders. This process can produce GN/Cu composites on a large scale, in which the in situ synthesized 3D GN not only maintains the perfect 3D network structure within the composites, but also has robust interfacial bonding with the metal matrix. As a consequence, the as-obtained 3D GN/Cu composites exhibit exceptionally high strength and superior ductility (the uniform and total elongation to failure of the composite are even much higher than the unreinforced Cu matrix). To the best of our knowledge, this work is the first report validating that a discontinuous 3D graphene-like network can simultaneously remarkably enhance the strength and ductility of the metal matrix.

Nowadays, robustly coupling electroactive inorganics with bicontinuous graphene-based films is highly desirable for high-performance energy storage devices and electrocatalysts. Herein, free-standing heteroatom-doped edge-enriched 3D rivet graphene (H-3DRG) film with high flexibility and conductivity was obtained as a substrate to deposit vertically arranged NiCo-layered double hydroxide (NiCo-LDH) nanoneedles via a hydrothermal approach and hierarchical NiCo₂S₄ nanostructures by further in situ anion exchange process without destroying the original vertical architecture. The carbon nanoparticles located on the surface of bicontinuous 3D porous graphene show gradient and edge-enriched structure, which can provide much more nucleation sites and better attachment of electroactive inorganics than traditional 3D porous graphene films with interconnected carbon layers prepared by the chemical vapor deposition process. Such outstanding structural advantages accelerate the reaction kinetics and enhance electrochemical activities which mean that H-3DRG@NiCo-LDH- and H-3DRG@NiCo₂S₄-based asymmetric supercapacitor devices both show high energy densities of 39.4 W h kg⁻¹ and 37.6 W h kg⁻¹ based on the entire devices, respectively. Furthermore, these hybrids also favor the oxygen evolution reaction process, which deliver a mass oxygen production current density of 10 mA cm⁻² at low overpotentials of 289 and 264 mV in 1 M KOH, respectively.

Novel interconnected sandwiched carbon-coated hollow nanostructures, i.e., carbon–shell/SnO₂–nanocrystal–layer/hollow–carbon–core, were developed as SIB anode materials.