Nitrogen and sulfur co-doped porous carbon nanosheets derived from willow catkin for supercapacitors

In recent years, nanocrystals of metal sulfide materials have attracted scientific research interest for renewable energy applications due to the abundant choice of materials with easily tunable electronic, optical, physical and chemical properties. Metal sulfides are semiconducting compounds where sulfur is an anion associated with a metal cation; and the metal ions may be in mono-, bi- or multi-form. The diverse range of available metal sulfide materials offers a unique platform to construct a large number of potential materials that demonstrate exotic chemical, physical and electronic phenomena and novel functional properties and applications. To fully exploit the potential of these fascinating materials, scalable methods for the preparation of low-cost metal sulfides, heterostructures, and hybrids of high quality must be developed. This comprehensive review indicates approaches for the controlled fabrication of metal sulfides and subsequently delivers an overview of recent progress in tuning the chemical, physical, optical and nano- and micro-structural properties of metal sulfide nanocrystals using a range of material fabrication methods. For hydrogen energy production, three major approaches are discussed in detail: electrocatalytic hydrogen generation, powder photocatalytic hydrogen generation and photoelectrochemical water splitting. A variety of strategies such as structural tuning, composition control, doping, hybrid structures, heterostructures, defect control, temperature effects and porosity effects on metal sulfide nanocrystals are discussed and how they are exploited to enhance performance and develop future energy materials. From this literature survey, energy conversion currently relies on a limited range of metal sulfides and their composites, and several metal sulfides are immature in terms of their dissolution, photocorrosion and long-term durability in electrolytes during water splitting. Future research directions for innovative metal sulfides should be closely allied to energy and environmental issues, along with their advanced characterization, and developing new classes of metal sulfide materials with well-defined fabrication methods.

Recent advances in metal sulfides: from controlled fabrication to electrocatalytic, photocatalytic and photoelectrochemical water splitting and beyond

Healable, adhesive, wearable, and soft human-motion sensors for ultrasensitive human–machine interaction and healthcare monitoring are successfully assembled from conductive and human-friendly hybrid hydrogels with reliable self-healing capability and robust self-adhesiveness. The conductive, healable, and self-adhesive hybrid network hydrogels are prepared from the delicate conformal coating of conductive functionalized single-wall carbon nanotube (FSWCNT) networks by dynamic supramolecular cross-linking among FSWCNT, biocompatible polyvinyl alcohol, and polydopamine. They exhibit fast self-healing ability (within 2 s), high self-healing efficiency (99%), and robust adhesiveness, and can be assembled as healable, adhesive, and soft human-motion sensors with tunable conducting channels of pores for ions and framework for electrons for real time and accurate detection of both large-scale and tiny human activities (including bending and relaxing of fingers, walking, chewing, and pulse). Furthermore, the soft human-motion sensors can be enabled to wirelessly monitor the human activities by coupling to a wireless transmitter. Additionally, the in vitro cytotoxicity results suggest that the hydrogels show no cytotoxicity and can facilitate cell attachment and proliferation. Thus, the healable, adhesive, wearable, and soft human-motion sensors have promising potential in various wearable, wireless, and soft electronics for human–machine interfaces, human activity monitoring, personal healthcare diagnosis, and therapy.

Wearable, Healable, and Adhesive Epidermal Sensors Assembled from Mussel-Inspired Conductive Hybrid Hydrogel Framework

Graphene is an atomically thin, two-dimensional (2D) carbon material that offers a unique combination of low density, exceptional mechanical properties, thermal stability, large surface area, and excellent electrical conductivity. Recent progress has resulted in macro-assemblies of graphene, such as bulk graphene aerogels for a variety of applications. However, these three-dimensional (3D) graphenes exhibit physicochemical property attenuation compared to their 2D building blocks because of one-fold composition and tortuous, stochastic porous networks. These limitations can be offset by developing a graphene composite material with an engineered porous architecture. Here, we report the fabrication of 3D periodic graphene composite aerogel microlattices for supercapacitor applications, via a 3D printing technique known as direct-ink writing. The key factor in developing these novel aerogels is creating an extrudable graphene oxide-based composite ink and modifying the 3D printing method to accommodate aero...

Supercapacitors Based on Three-Dimensional Hierarchical Graphene Aerogels with Periodic Macropores.

Carbon nanotube- and graphene-based nanomaterials and applications in high-voltage supercapacitor: A review

Densely packed graphene nanomesh-carbon nanotube hybrid film for ultra-high volumetric performance supercapacitors

Currently, carbon materials, such as graphene, carbon nanotubes, activated carbon, porous carbon, have been successfully applied in energy storage area by taking advantage of their structural and functional diversity. However, the development of advanced science and technology has spurred demands for green and sustainable energy storage materials. Biomass-derived carbon, as a type of electrode materials, has attracted much attention because of its structural diversities, adjustable physical/chemical properties, environmental friendliness and considerable economic value. Because the nature contributes the biomass with bizarre microstructures, the biomass-derived carbon materials also show naturally structural diversities, such as 0D spherical, 1D fibrous, 2D lamellar and 3D spatial structures. In this review, the structure design of biomass-derived carbon materials for energy storage is presented. The effects of structural diversity, porosity and surface heteroatom doping of biomass-derived carbon materials in supercapacitors, lithium-ion batteries and sodium-ion batteries are discussed in detail. In addition, the new trends and challenges in biomass-derived carbon materials have also been proposed for further rational design of biomass-derived carbon materials for energy storage.

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Biomass-derived carbon materials with structural diversities and their applications in energy storage

Supercapacitors, also known as electrochemical capacitors, can provide much faster charge–discharge, greater power density, and cyclability than batteries, but they are still limited by lower energy densities (or the amount of energy stored per unit volume). Here, a novel strategy for the synthesis of functional pillared graphene frameworks, in which graphene fragments in-between graphene sheets, through simple thermal-treatment of ozone (O3)-treated graphene oxide at very low temperature of 200 °C is reported. Due to its high packing density, high content of stable oxygen species, and continues ion transport network in-between graphene sheets, the functional pillared-graphene framework delivers not only high gravimetric capacitance (353 F g−1 based on the mass of the active material) and ultrahigh volumetric capacitance (400 F cm−3 based on total mass of electrode material) in aqueous electrolyte but also excellent cyclic stability with 104% of its initial capacitance retention after 10 000 cycles. Moreover, the assembled symmetric supercapacitor achieves as high as 27 Wh L−1 of volumetric energy density at a power density of 272 W L−1. This novel strategy holds great promise for future design of high volumetric capacitance supercapacitors.

Functional Pillared Graphene Frameworks for Ultrahigh Volumetric Performance Supercapacitors

A flexible, bubble‐decorated, honeycomb‐like graphene film (BHGF) is fabricated by a low‐temperature heat treatment of graphene oxide film. The as‐prepared BHGF exhibits an ultrahigh sensitivity of 161.6 kPa−1 at a strain less than 4%, due to the switching effect depended on “point‐to‐point” and “point‐to‐face” contact modes.

Lizhi Sheng

Papers

Densely packed graphene nanomesh-carbon nanotube hybrid film for ultra-high volumetric performance supercapacitors

Biomass-derived carbon materials with structural diversities and their applications in energy storage

Functional Pillared Graphene Frameworks for Ultrahigh Volumetric Performance Supercapacitors

Bubble‐Decorated Honeycomb‐Like Graphene Film as Ultrahigh Sensitivity Pressure Sensors

Multilayer-Folded Graphene Ribbon Film with Ultrahigh Areal Capacitance and High Rate Performance for Compressible Supercapacitors