Bioinspired tailoring of nanoarchitectured nickel sulfide@nickel permeated carbon composite as highly durable and redox chemistry enabled battery-type electrode for hybrid supercapacitors† Mohan Reddy Pallavolu, a Ramesh Reddy Nallapureddy, a Hemachandra Rao Goli, b Arghya Narayan Banerjee, * a Gutturu Rajasekhara Reddy a and Sang W. Joo * a Rational design of highly conductive and redox-active electrode materials composed of metal chalcogenides and carbon composites has attracted promising attention for the development of high- performance energy storage devices. Herein, cost-effective in situ design of carbon sheets with nickel sulfide shielded nickel (NiS–Ni@C) nanocomposite is prepared using biomass precursor with subsequent pyrolysis and sulfurization, respectively. Initially, highly conductive nickel nanospheres are permeated into carbon sheets (Ni@C) by the pyrolysis of carbon-rich wheat snacks and nickel salt. Following, core– shell-like hierarchical NiS flowers on Ni@C were derived in situ using various thiourea concentrations under hydrothermal treatment. Utilizing the hierarchical NiS–Ni@C as an electrode material, the highly conductive composite enables rapid diffusion of electrolyte ions into their interiors and accelerates redox chemistry during electrochemical measurements. Specifically, hierarchical NiS–Ni@C nanocomposite demonstrates dominant battery-type behavior with a maximum specific capacity of 430 Cg 1 and excellent cycling stability of 92%. Moreover, a hybrid supercapacitor is assembled using hierarchical NiS–Ni@C as a positive electrode and wheat-snack derived porous carbon as a negative electrode, which exhibits superior energy and power densities with good cycling stability. The designed composite using biomass sources promotes the way for the development of highly active electrode materials for energy storage and electrocatalytic applications. 1. Introduction The collectively growing environmental issues, depletion of fossil fuel sources, and increased energy requirements have prompted researchers to develop eco-benign energy storage technologies, which ensure high-level safety and low cost. 1,2 Energy storage technologies in the form of metal-ion batteries and supercapacitors are widely utilized in various electronic appliances, including mobile phones, laptops, pacemakers, and hybrid electric vehicles. 3–5 Particularly, supercapacitors (SCs) are emerging as safe energy storage devices among existing devices due to their environmental friendliness, high-end safety, long cycle lifetime, high specic power, low cost, and fast charging and discharging process. 6 However, the electro- static charge storage mechanism of SCs via the reversible physical adsorption of ions on the surface of the electrode and electrolyte interface initiated the limited energy density. 7,8 This could largely halt their usability in wide automotive applica- tions, where higher energy density is needed. 9 Recently, the rational design of hybrid supercapacitors (HSCs) has been considered as an attractive alternative for addressing intermit- tent energy concerns due to their advantages of mixed energy storage mechanisms and wide-operating voltages. 10 HSCs are generally designed using battery-type transition metal oxides as positive and capacitive-type carbon-based materials as negative electrodes in a single paradigm. 11 In order to achieve superior energy storage performance, hierarchical design of battery-type materials with high conductivity, abundant redox sites and ultralong structural durability are immediately required. 12,13 Recently, hierarchically structured transition metal hydroxides/oxides, including layered double hydroxide (LDH) NiCo-LDHs, Co 3 O 4 , LiMn 2 O 4 , CoMoO 4 , ZnCo 2 O 4 , CoNiWO 4 , and Co–NiV 2 O 8 have been widely used as battery-type electrodes in HSCs due to their high theoretical capacity, multiple valency states, excellent electrochemical activity, and natural avail- ability. 10,14–19 The drawbacks accompanied by low conductivity and poor electron transfer rate of the materials limit the prac- tical applicability in device applications. On the other hand, a School of Mechanical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea. E-mail: arghya@ynu.ac.kr; swjoo@yu.ac.kr b Department of Physics, Banasthali University, Banasthali, Rajasthan, 304022, India † Electronic supplementary information (ESI) available. See DOI: 10.1039/d1ta08122e Cite this: J. Mater. Chem. A, 2021, 9, 25208 Received 21st September 2021 Accepted 22nd October 2021 DOI: 10.1039/d1ta08122e rsc.li/materials-a 25208 | J. Mater. Chem. A, 2021, 9, 25208–25219 This journal is © The Royal Society of Chemistry 2021 Journal of Materials Chemistry A PAPER Published on 22 October 2021. Downloaded by Yeungnam University on 11/17/2021 12:15:20 AM. View Article Online View Journal | View Issue