Nickel sulfide-based energy storage materials for high-performance electrochemical capacitors

Abstract

Supercapacitors are favorable energy storage devices in the field of emerging energy technologies with high power density, excellent cycle stability and environmental benignity. The performance of supercapacitors is definitively influenced by the electrode materials. Nickel sulfides have attracted extensive interest in recent years due to their specific merits for supercapacitor application. However, the distribution of electrochemically active sites critically limits their electrochemical performance. Notable improvements have been achieved through various strategies such as building synergetic structures with conductive substrates, enhancing the active sites by nanocrystallization and constructing nanohybrid architecture with other electrode materials. This article overviews the progress in the reasonable design and preparation of nickel sulfides and their composite electrodes combined with various bifunctional electric double-layer capacitor (EDLC)-based substances (e.g., graphene, hollow carbon) and pseudocapacitive materials (e.g., transition-metal oxides, sulfides, nitrides). Moreover, the corresponding electrochemical performances, reaction mechanisms, emerging challenges and future perspectives are briefly discussed and summarized.

Single‐Crystal Nano‐Subunits Assembled Accordion‐Shape WNb2O8 Framework with High Ionic/Electronic Conductivities towards Li‐Ion Capacitors

“…[ 1,2 ] Among various emerging energy sources, electrochemical energy storage devices (EESDs) represented by Li‐ion batteries (LIBs) and supercapacitors (SCs) have been extensively used in our daily life due to their blessings of large energy density and high power properties, respectively. [ 3–5 ] However, each of them when singly operating cannot simultaneously achieve both larger energy and power densities in one electrochemical device. The exploitation in new EESDs with super electrochemical performance in both energy and power aspects is therefore more meaningful to meet the hash requirements nowadays.…”

Superior supercapacitive performance of Cu2MnSnS4 asymmetric devices

“…Various transition metal sulfide electroactive materials for electrochemical capacitors (ECs) have been explored due to their rich valence and desirable chemical stability [17,18]. Sulfides are considered to be an excellent pseudocapacitive material, especially for their multiple redox reactions, improved electrical conductivity, low band gap, which leads to superior performance, better oxidation state and longer cycling when compared to metal oxides/hydroxides [19,20]. In general, the pseudo-capacitance capabilities of these sulfides in alkaline solutions are exhibited faradic reaction associated with the mutual transformation of ion diffusion into the electrode materials with rich electroactive sites.…”

Construction of NiCo2O4/O-g-C3N4 Nanocomposites: A Battery-Type Electrode Material for High-Performance Supercapacitor Application

“…As renewable energy is elevating our daily lives effectively and due to the sporadic nature of renewable energy resources, there is demand for the development of high-performance energy storage devices with low cost. In this regard, electrochemical energy storage systems play a vital role by effectively storing renewable energy resources. − Among the various energy storage devices, supercapacitors or ultracapacitors have gained huge research interest because of their unique properties such as fast charge–discharge behavior, high power densities, and long cyclic stability. − On the basis of the charge storage mechanism, supercapacitors can be divided into two types: (i) pseudocapacitors (where charge storage is based on the surface redox reactions of electroactive species) and (ii) electrolytic double-layer capacitors (EDLCs) (where charge storage is due to the accumulation of electrostatic charge at the electrode/electrolyte interface). − Both charge storage mechanisms are involved in a hybrid system. , Compared to both types of supercapacitive electrode materials, a higher specific capacitance value has been observed for metal-oxide-based materials than carbonaceous and conducting polymers because they have variable oxidation states for a reversible faradic reaction.…”