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[Display omitted] • NiO/Peanut shell activated carbon (Ni/PSAC) using wet impregnation method. • Ni/PSAC electrode delivered a specific capacitance of 848F g−1 at 8 A g−1. • Asymmetric device reporting energy density of 39.14 Wh kg−1. • For waste-to-effective energy storage, it is an excellent strategy. The approach outlined in this study provides insights into developing sustainable and cost-effective energy storage solutions utilizing agricultural waste materials focusing on using peanut shells to make activated carbon with subsequent impregnation of NiO for supercapacitor electrodes. X-ray diffraction analysis showed the NiO-impregnated peanut shell-activated carbon (Ni/PSAC) nanocomposite material had a face-centered cubic structure. The electrochemical behavior of Ni/PSAC electrode and Ni/PSAC//AC device were comprehensively deliberated through cyclic voltammetry (CV), Galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The GCD data of Ni/PSAC//AC device uncovered a boosted specific capacitance of 154.63F g−1, accompanied by an energy density of 39.14 Wh kg−1 and a power density of 2700 W kg−1 at 2 A g−1 current density. These findings suggest the potential of mesoporous Ni/PSAC electrode as an efficient and hopped-up material for asymmetric supercapacitor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Self-O-doped Alpinia galanga stem-based carbon nanofiber succesfully synthesis. • The hierarchical porous carbon exhibit high specific surface area of 1065.58 m2/g. • The porous carbon was performed in solid-free binder form. • In 2-electrode system, supercapacitor possessed specific capacitance of 226F g−1. In this study, activated carbon with hierarchical pores and a nanofiber structure doped with oxygen was prepared using a pure biomass-based sustainable strategy involving integrated chemical impregnation and pyrolysis. Alpinia galangal stem was chosen as it functions as fast conductive network with abundant electrochemical active sites for high-grade electrode materials. The optimal precursor exhibited self-doping of oxygen ranging from 6.15 to 15.69 % with 1065.58 m2/g, which contributed to the redox reaction of the electrode material. When tested in a 2-electrode system, the porous carbon nanofibers showed a high specific capacitance of 226F g−1 at 1 A g−1 in 1 M H 2 SO 4 electrolyte, producing an energy density of 9.3483 Wh kg−1 with a coulombic efficiency of 89.01 %. The results showed that oxygen-doped hierarchical porous carbon nanofibers produced from Alpinia galangal stem biomass and designed to be solid-free of binders are highly promising as high-quality electrode materials that can improve sustainable supercapacitor performance. [ABSTRACT FROM AUTHOR]

• Sulfur-rich WS 2 /WO 3 electrodes reached a specific capacitance of 570.1 F/g. • Battery-type behavior in WS 2 /WO 3 electrodes was identified using power law. • WS 2 /WO 3 //AC device revealed energy and power density of 55.6 Wh/kg and 1335 W/kg. • Capacitance retention and columbic efficiency were 87.4% and 99.8% for 5000 cycles. Active sites enriched WS 2 quantum dot decorated WO 3 electrode was designed for supercapacitor application, using hydrothermal and sonication techniques. The WS 2 /WO 3 electrode exhibited a specific capacitance of 570.1 F/g at 1 A/g due to numerous active sites, and facile electrolyte accessibility. The battery-type WS 2 /WO 3 //AC asymmetric supercapacitor device achieved an energy and power density of 55.6 Wh/kg and 1335 W/kg, and a notable retention capacitance and columbic efficiency of 87.4 % and 99.8 % for 5000 cycles at 6A/g, respectively. The results highlight WS 2 /WO 3 as a promising electrode for supercapacitors. [ABSTRACT FROM AUTHOR]

N-doped hierarchical porous carbon as an excellent electrode material in symmetric supercapacitor is fabricated by a facile and green method. [Display omitted] • N-doped porous carbon is prepared from one-step pyrolysis of glycine and Na 2 CO 3. • It exhibits a high capacitance of 207 F/g at 20 A/g in a symmetric supercapacitor. • 99.95% of initial capacitance remains after 10,000 cycles at 5 A/g. • A high energy density of 28.8 Wh/kg is obtained at a power density of 20 KW/kg. N-doped hierarchical porous carbon (NHPC) was facilely fabricated by a one-step pyrolysis of glycine and water-soluble Na 2 CO 3 , which is employed as a renewable water-soluble template without additional corrosive activating reagent. Benefiting from the hierarchical porous structure, high specific surface area (2735 m2 g−1) and the suitable nitrogen content of 3.84 at%, the obtained porous carbon exhibits a high specific capacitance (C sp) of 267 F g−1 at 0.2 A g−1 in a three-electrode system and 201 F g−1 at 0.2 A g−1 in the symmetric supercapacitor. More importantly, it shows an impressive rate capability of 102 % retention at 20 A g−1, outstanding cycling stability with 99.95 % of capacitance retention at 5 A g−1 after 10,000 cycles and a high energy density of 28.8 Wh kg−1 at a power density of 20 KW kg−1 in the symmetric supercapacitor. The results indicate that the synthesized NHPC obtained from this simple synthesis method would be an effective electrode material for symmetric supercapacitors, and this eco-friendly and easily scaled-up approach would provide a valuable strategy for the synthesis of porous carbon materials. [ABSTRACT FROM AUTHOR]

• Tubular Cu 2 MoS 4 /MWCNTs were prepared as supercapacitor negative electrode material. • Appropriate MWCNTs addition significantly optimized the electrochemical performance. • CMS/MWCNTs-0.15@CC exhibits a highest specific capacitance of 219F g−1 at 0.5 A g−1. • The device with a voltage window of 1.8 V yields an energy density of 24.5 Wh kg−1 at 900 W kg−1. The ternary layered Cu 2 MoS 4 (CMS) has been proven to be a potential supercapacitor negative electrode material. However, its inherent low conductivity and limited diffusion dynamics usually result in unsatisfactory specific capacitance and rate performance. Therefore, hollow tubular CMS and CMS/MWCNTs-0.05, 0.15, 0.25 composite materials were prepared by a one-pot hydrothermal method in this work. The addition of MWCNTs improves the electrical conductivity and provides an efficient three-dimensional electronic transport network. Due to the smallest resistance and optimized porous structure with large surface area, CMS/MWCNTs-0.15@CC exhibits a highest specific capacitance (C s) of 219F g−1 at 0.5 A g−1, which is 2.45 times that of CMS@CC. The assembled Ni-Co-S@CC//CMS/MWCNTs-0.15@CC supercapacitor with a voltage window of 1.8 V yields a maximum energy density of 24.5 Wh kg−1 at 900 W kg−1. [ABSTRACT FROM AUTHOR]