Recent advancements in supercapacitor technology

Over the past decade, electrochemical energy storage (EES) devices have greatly improved, as a wide variety of advanced electrode active materials and new device architectures have been developed. These new materials and devices should be evaluated against clear and rigorous metrics, primarily based on the evidence of real performances. A series of criteria are commonly used to characterize and report performance of EES systems in the literature. However, as advanced EES systems are becoming more and more sophisticated, the methodologies to reliably evaluate the performance of the electrode active materials and EES devices need to be refined to realize the true promise as well as the limitations of these fast-moving technologies, and target areas for further development. In the absence of a commonly accepted core group of metrics, inconsistencies may arise between the values attributed to the materials or devices and their real performances. Herein, we provide an overview of the energy storage devices from conventional capacitors to supercapacitors to hybrid systems and ultimately to batteries. The metrics for evaluation of energy storage systems are described, although the focus is kept on capacitive and hybrid energy storage systems. In addition, we discuss the challenges that still need to be addressed for establishing more sophisticated criteria for evaluating EES systems. We hope this effort will foster ongoing dialog and promote greater understanding of these metrics to develop an international protocol for accurate assessment of EES systems.

Towards establishing standard performance metrics for batteries, supercapacitors and beyond.

The exploration of renewable, cost-effective, and environmentally friendly electrode materials with high adsorption, fast ion/electron transport, and tunable surface chemistry is urgently needed for the development of next-generation biocompatible energy-storage devices. In recent years, biomass-derived carbon electrode materials for energy storage have attracted significant attention because of their widespread availability, renewable nature, and low cost. More importantly, their inherent uniform and precise biological structures can be utilized as templates for fabricating electrode materials with controlled and well-defined geometries. Meanwhile, the basic elements of biomass are carbon, sulfur, nitrogen, and phosphorus. The special naturally ordered hierarchical structures as well as abundant surface properties of biomass-derived carbon materials are compatible with electrochemical reaction processes such as ion transfer and diffusion. To date, a series of novel porous carbon materials with different dimensions have been prepared by various methods using biomass as the raw material, which is an important field in the fabrication of supercapacitor electrode materials. Herein, we summarized recently reported biomass-derived carbon materials with one-dimensional, two-dimensional, and three-dimensional structures and their applications as carbon-based electrode materials for supercapacitors. Finally, the current challenges and future perspectives of the carbon-based electrode materials with respect to the supercapacitor's performance were closely highlighted.

Biomass-derived porous carbon materials with different dimensions for supercapacitor electrodes: a review

Transition metal nitrides (TMNs), by virtue of their unique electronic structure, high electrical conductivity, superior chemical stability, and excellent mechanical robustness, have triggered tremendous research interest over the past decade, and showed great potential for electrochemical energy conversion and storage. However, bulk TMNs usually suffer from limited numbers of active sites and sluggish ionic kinetics, and eventually ordinary electrochemical performance. Designing nanostructured TMNs with tailored morphology and good dispersity has proved an effective strategy to address these issues, which provides a larger specific surface area, more abundant active sites, and shorter ion and mass transport distances over the bulk counterparts. Herein, the most up-to-date progress on TMN-based nanomaterials is comprehensively reviewed, focusing on geometric-structure design, electronic-structure engineering, and applications in electrochemical energy conversion and storage, including electrocatalysis, supercapacitors, and rechargeable batteries. Finally, we outline the future challenges of TMN-based nanomaterials and their possible research directions beyond electrochemical energy applications.

Transition metal nitrides for electrochemical energy applications.

The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field. Smart textile-integrated microelectronic systems (STIMES), which combine microelectronics and technology such as artificial intelligence and augmented or virtual reality, have been intensively explored. A vast range of research activities have been reported. Many promising applications in healthcare, the internet of things (IoT), smart city management, robotics, etc., have been demonstrated around the world. A timely overview and comprehensive review of progress of this field in the last five years are provided. Several main aspects are covered: functional materials, major fabrication processes of smart textile components, functional devices, system architectures and heterogeneous integration, wearable applications in human and nonhuman-related areas, and the safety and security of STIMES. The major types of textile-integrated nonconventional functional devices are discussed in detail: sensors, actuators, displays, antennas, energy harvesters and their hybrids, batteries and supercapacitors, circuit boards, and memory devices.

Smart Textile-Integrated Microelectronic Systems for Wearable Applications

Research progress on conducting polymer based supercapacitor electrode materials

Preparation and thermoelectric properties of SWCNT/PEDOT:PSS coated tellurium nanorod composite films

Preparation and thermoelectric properties of PEDOT:PSS coated Te nanorod/PEDOT:PSS composite films

Progress on PEDOT:PSS/Nanocrystal Thermoelectric Composites

In this work, polyvinylpyrrolidone (PVP) coated Ag-rich Ag2Te nanowires (NWs) were synthesized by a wet chemical method using PVP coated Te NWs as templates, and a flexible PVP/Ag/Ag2Te ternary com...

Qiufeng Meng

Papers

Research progress on conducting polymer based supercapacitor electrode materials

Preparation and thermoelectric properties of SWCNT/PEDOT:PSS coated tellurium nanorod composite films

Preparation and thermoelectric properties of PEDOT:PSS coated Te nanorod/PEDOT:PSS composite films

Progress on PEDOT:PSS/Nanocrystal Thermoelectric Composites

High Performance and Flexible Polyvinylpyrrolidone/Ag/Ag2Te Ternary Composite Film for Thermoelectric Power Generator.