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A strategy to prepare facile electrode materials for electrochemical capacitors with high conductivity, high surface area and hierarchical pore structure along with nitrogen functional groups to enhance the electrochemical performance, is presented in this work. Partially unravelled carbon nanotubes (PURNTs) are interconnected to the wrinkled few layered graphene nanosheets (WfG), which act as quick ion and charge transportation channels. Here, PURNTs acts as a spacer to the WfG to avoid the restacking. Though WfG-PURNTs exhibit good results, to further improve the electrochemical performance we developed an electrode material by designing nitrogen-doped porous carbon covered favorably interconnected WfG-PURNTs with interconnected pore structure. The WfG-PURNTs serve as the conductive matrix, which plays a key role in enhancing the N-PC (WfG-PURNTs) electrode material's electrochemical performance. And the nitrogen functional groups, through faradaic red-ox reactions, contribute to the pseudocapacitance in addition to the electric double layer capacitance, thereby enhancing overall supercapacitive performance. The developed N-PC (WfG-PURNTs)-700 shows a high nitrogen amount of 6.8 at %, with a high active surface area of 2418 m2 g−1. The synergistic effect of the WfG-PURNTs and N-doped porous carbon results in high supercapacitive performance and better cyclic stability. It shows an excellent specific capacitance (Cp) of 954 F g−1 at high current density of 2 A g−1. Also, the assembled symmetric supercapacitors show high energy densities of 61.1, 119.4, and 195.4 Wh kg−1 in acidic, neutral and ionic liquid electrolytes, respectively. We also designed asymmetric solid-state flexible supercapacitor which exhibits a high specific capacitance of 209.4 F g−1 at 2 A g−1 and an excellent energy density of 29.15 Wh kg−1. Furthermore, the assembled three such flexible supercapacitors in series connection, could able to light up red colored LED for 30 min once charged for 60 s. [Display omitted] • Novel N-doped porous carbon hybrid electrode materials are developed. • They exhibit high conductivity, large surface area and hierarchical porous structure. • The fabricated SSC presents outstanding energy densities in various electrolytes. • The flexible SSC exhibits an excellent energy density of 29.15 Wh kg−1. [ABSTRACT FROM AUTHOR]

Herein, we present a simple, large-scale and low-cost process to develop hierarchically porous N–S co-doped 3D wrinkled graphene like nanosheets (3D H-GNS) from carbonization of biomass Tender palm shoots and NaHCO 3. Non-corrosive and non-toxic Na 2 CO 3 acts as a reaction mean to control the activation process, developing 3D H-GNS with a high specific surface area of 2095 m2 g−1. A 3D H-GNS-900 electrode exhibits a high specific capacitance of 529 F g−1 (1.5 A g−1) and 330 F g−1 (1 A g−1) in 1 M H 2 SO 4 for 3-electrode and 2-electrode systems respectively. Further, a longer cycle life with 93% capacitance retention over 10,000 cycles at 5 A g−1 is realized. Also, we are successful in fabricating biocompatible solid-state flexible supercapacitor device with 3D H-GNS-900 electrodes in organic electrolyte with 3 V voltage range, demonstrating to run a toy fan and lightning a LED for 15 min after charging for 60 s. Image 1 • Novel self N–S co-doped 3D wrinkled graphene like nanosheets (3D H-GNS) are developed from biomass Tender palm shoots. • As-prepared 3D H-GNS exhibit high specific surface area and unique porous morphology. • High specific capacitance of 529 F g−1 at 1.5 A g−1 and excellent energy density of 106.3 Wh kg−1 in organic electrolyte is achieved. • Fabricated fully bio-compatible solid-state flexible supercapacitor presents electrochemical stability up to 2000 bending angles. [ABSTRACT FROM AUTHOR]

Thermal sprayed Cr 3 C 2 -NiCr coatings are widely used to protect industrial components from ambient or elevated erosive degradation. Various thermal spraying techniques such as plasma spray, detonation spray (DS), high velocity oxy-fuel (HVOF) and high velocity air-fuel spray (HVAF) are widely used to deposit Cr 3 C 2 -NiCr coatings. The choice of thermal spraying technique governs the inflight particle velocity and temperature, resulting in unique coating microstructural features, characteristics and erosion performance. In this study, Cr 3 C 2 -NiCr coatings are deposited through HVAF, DS and axial plasma spray. A comprehensive comparative analysis was performed to understand the process-structure-property relationship of Cr 3 C 2 -NiCr coatings, which correlated with the room and high temperature erosion performance. HVAF spray deposited Cr 3 C 2 -NiCr coatings with preferred microstructural features and properties, ensuring superior (high/room temperature) erosive resistance. Cr 3 C 2 -NiCr coatings deposited via DS spray performed second best, while plasma sprayed exhibited defective microstructure with inferior mechanical properties, resulting in substandard erosion performance. [Display omitted] • The deposition technique greatly influenced the coating microstructure and properties. • HVAF spray deposited coatings with desirable microstructure and properties. • Detonation spray offered the second-best microstructure and properties. • At elevated conditions, coatings displayed better erosion resistance than boiler steel. [ABSTRACT FROM AUTHOR]