A green, versatile, and universal H 2 O 2 activation method is proposed to improve the capacitive properties of high-mass loading wood-based supercapacitors. 

High performance supercapacitors based on wood-derived thick carbon electrodes synthesized <i>via</i> green activation process

Voltage holding and self-discharge phenomenon in ZnO-Co3O4 core-shell heterostructure for binder-free symmetric supercapacitors

Nowadays, the energy storage systems based on lithium-ion batteries, fuel cells (FCs) and super capacitors (SCs) are playing a key role in several applications such as power generation, electric vehicles, computers, house-hold, wireless charging and industrial drives systems. Moreover, lithium-ion batteries and FCs are superior in terms of high energy density (ED) as compared to the SCs. But, the down-side associated with them is the low power density (PD). On the other hand, this high PD feature is essential for the enhancement of dynamic performance of the system. Therefore, the SCs are well utilized due to their dominant features such as high specific power, rapid charging-discharging rate and superior cycling life. Hence, this paper mainly focuses on the advancements of various types of SCs along with their performance improvement methods. The important properties and selection of the electrode and electrolyte materials are described in detail. The commercially available SCs are enumerated with much more emphasis on their Figure of Merits (FOMs). Furthermore, the prominent role of SCs is highlighted with respect to the aforementioned applications. Finally, the future challenges associated with the SCs are presented. This review paper gives insightness for the design engineers and researchers in order to fill the research gaps associated with the SCs. 

Super capacitors for energy storage: Progress, applications and challenges

With the ongoing advance of flexible energy storage products for commercial portable electronics application, the fundamental comprehension of the temperature-dependence for supercapacitors is in urgent demand. Although polypyrrole (PPy) has been extensively employed as electrodes for supercapacitor systems, their electrochemical response to extreme thermal environments is rarely discussed. In this work, PPy was rationally constructed on the surface of carbon cloth (CC) as electrodes and a type of high-performance flexible symmetric supercapacitor was assembled with a PVA-H3PO4 gel electrolyte. The electrochemical performance of the supercapacitors was systematically investigated at various surrounding temperatures from 0 °C to 60 °C using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy measurements. The results demonstrated that the areal specific capacitance of the CC/PPy supercapacitor at 0.5 mA cm−2 increased from 52.91 mF cm−2 to 75.08 mF cm−2 and the internal resistance fell by 71.4% when the operating temperature rose from 0 °C to 60 °C. Moreover, cycling stability dropped and the self-discharge behavior accelerated in the supercapacitors with the gradual increase in the external temperature. This study provides a fundamental understanding of the temperature-dependent pseudocapacitive performance of PPy-based flexible supercapacitors, which gives a valuable reference for energy storage system applications.

Thermal effect on the pseudocapacitive behavior of high-performance flexible supercapacitors based on polypyrrole-decorated carbon cloth electrodes

Graphene Fibers Containing Activated Graphene for High-Performance Solid-State Flexible Supercapacitors

Wire supercapacitors are promising flexible power sources for wearable devices because of their high power density, long cycle life, and mechanical flexibility However, obtaining high energy density along with thermal stability is essential for developing sustainable wire supercapacitors that use a charge storage mechanism based on electric double-layer (EDL) formation In this study, activated graphene (AG) was coated onto continuous graphene deposited on Cu wire current collectors using electrophoretic deposition, forming wire supercapacitors with high power and energy density as well as outstanding thermal stability and chemical resistance The incorporation of AG, which has a high specific surface area, enabled nearly ideal capacitive behaviors of the devices with high specific areal capacitances of up to 1303 mF cm−2 Multilayer graphene grown by chemical vapor deposition (CVD) on Cu wires worked as a multifunctional intermediate layer for enhancing the interfacial contact between the electrode and the current collector as well as the electrical conductivity, chemical resistance, and thermal stability of the Cu wire The great synergy between the AG electrode material and CVD-grown graphene on Cu current collectors achieved high energy densities of up to 454 μW h cm−2 and outstanding power densities of up to 161 mW cm−2 with excellent cycling stability (∼938% capacitance retention over 10 000 cycles) Furthermore, the wire supercapacitors exhibited stable EDL charge storage capability for temperatures ranging from 7 to 80 °C This unique architecture of wire supercapacitors promises great potential for high-performance and thermostable energy storage, and can be embedded in future wearable electronics and smart textiles

Ba Trung Ho

Papers

Graphene Fibers Containing Activated Graphene for High-Performance Solid-State Flexible Supercapacitors

High-performance and thermostable wire supercapacitors using mesoporous activated graphene deposited on continuous multilayer graphene