One of the most exciting new developments in energy storage technology is Zn‐ion hybrid supercapacitors (ZHSCs). ZHSCs combine Zn‐ion batteries with supercapacitors (SCs) to address the energy and power needs of portable devices and electric automobiles. Low energy density and the development of cathode material are significant issues for ZHSCs. This review provides an in‐depth investigation of charge storage mechanisms from SCs to ZHSCs. The advantages/disadvantages of ZHSCs, the recent development of cathode materials, and the new design for device fabrications are critically summarized. New cathode materials should be developed to achieve high energy density while preserving the inherent power capability and stability. People increasingly engage with smart electronic and hybrid gadgets, demanding flexible, resilient, and highly safe energy storage devices. ZHSC has emerged as a complete alternative to risky sodium‐ion/lithium‐ion technologies. An overview of all reported carbon‐based, biomass‐derived carbons, metal oxides, MOFs, COFs, MXenes, graphene, and composite materials employed for ZHSCs is comprehensively provided. Furthermore, cathode materials for flexible, micro, wire‐shaped, printed, and photo‐rechargeable ZHSCs are also examined with their practical challenges. This review is anticipated to offer valuable recommendations for designing and manipulating cathode materials for high‐performance ZHSCs to achieve real‐world applications.

Fundamentals and Scientific Challenges in Structural Design of Cathode Materials for Zinc‐Ion Hybrid Supercapacitors

Metal doped graphene oxide derived from Quercus ilex fruits for selective and visual detection of iron(III) in water: Experiment and theory

Cobalt phosphate (Co3(PO4)2) has been recognized as a biomimetic superoxide anion (O2•–) sensing material, but there is a great challenge to achieve high sensitivity due to its relatively poor cond...

Cobalt Phosphates Loaded into Iodine-Spaced Reduced Graphene Oxide Nanolayers for Electrochemical Measurement of Superoxide Generated by Cells

The semiconductor, Bi2Se3 layers was electrochemically deposited on Indium Tin Oxide substrate (ITO) from a nitric acid, Bi (NO3)3·5H2O and H2SeO3 solution. The results of the electrochemical behavior of Bi2Se3 were as follows: Cyclic voltammetry (CV) studies revealed that the electrodeposition of Bi2Se3 was performed at a negative potential of −0.22 V vs SCE, according to a quasi-reversible reaction controlled by the diffusion process. Chronoamperometry (CA) showed that the electrodeposition of Bi2Se3 follows a 3D instantaneous nucleation model with diffusion-controlled growth. X-ray diffraction analysis indicated that the resulting layers at −0.22 V vs SCE exhibited a Rhombohedral Bi2Se3 structure with a preferred orientation (1 1 3) and the 2:3 stoichiometric ratio of Bi and Se was checked by EDS quantitative analysis. SEM images revealed the formation of a uniform size mainly consisting of nanoparticles with spherical shapes. The Bi2Se3 obtained layers are n-type semiconductors with an optical band gap of 2.35 eV. 

Electrochemical properties of Bi2Se3 layers semiconductor elaborated by electrodeposition

Tin selenide, which possesses merits of attractive theoretical capacity, inexpensiveness, and low toxicity, is an appealing candidate for next generation anode material of lithium ion batteries (LIBs). However, it suffers from the severe volume variation, aggregation, and weak conductivity. To tackle these issues, we report an in situ preparation of composite of SnSe coupled with nitrogen/sulfur dual-doped rGO (SnSe@N/S-rGO), serving as the superior anode material of LIBs. Notably, the SnSe nanoparticles are uniformly anchored on rGO, with nitrogen doping carbon enhancing the electrical conductivity and sulfur doping generating lattice defects on the surface of carbonaceous materials to provide more active sites. Under 200 mA g−1, this material could display a high capacity up to 785 mAh g−1 over 100 cycles, which is a highly encouraging electrochemical performance for the anode of LIBs.

SnSe coupled with nitrogen/sulfur dual-doped rGO for superior anode of lithium ion batteries

Intercalation pseudocapacitance in Bi2Se3−MnO2 nanotube composite for high electrochemical energy storage

This paper details an approach for the synthesis of stable electroactive Au–V2O5–MnO2 nanoflower composites using a simple redox-mediated methodology under modified hydrothermal (MHT) conditions. The nanocomposite was characterized by various techniques like X-ray diffraction, scanning electron microscopy, high-resolution transmisson electron microscopy, and X-ray photoelectron spectroscopy. MnO2 and Au formed a profitable hierarchical network morphology in the interstitial sites of V2O5, and this kind of synergetic architecture exhibits an elevated specific capacitance (388 F g–1 at 1 A g–1) compared to commercial V2O5 (85 F g–1 at 1 A g–1) in a neutral electrolyte. The as-synthesized nanocomposite contributed more to energy storage with superior energy density (49 Wh kg–1 at 1 A g–1 current density) and power density (4 kW kg–1 at 10 A g–1 current density) and demonstrated improved stability compared to commercial V2O5 of up to 2000 continuous charge/discharge cycles in a two-electrode system. Temperature- and field-dependent [both direct-current (dc) and alternating-current (ac)] studies exhibited enhanced conductance due to the incorporation of Au and MnO2 and non-Ohmic electrical conduction, characterized by the onset voltage V0 (dc) and onset frequency f0 (ac). These two onset parameters followed power-law behavior with Ohmic conductance with two onset exponents (xV and xf). Such electrical transport properties were explained using intrachain hopping conduction of charge carriers within the layers of pristine V2O5 and hopping of charge carriers between the layers of V2O5 in the Au–V2O5–MnO2 nanocomposite and supported the interstitial incorporation of the compounds. 

Redox-Guided Synthesis of Au–V2O5–MnO2 Nanoflower Composites with Enhanced Electrical Conductance for Supercapacitor Applications

In this paper, we report the fundamental electrical transport properties measured in Bi2Se3-AgMnOOH nanocomposite disc, which is prepared for the first time by convenient low temperature solution-phase chemistry in conjunction with redox-mediated methodology. The comparative structural and morphological analyses for the nanocomposite with pristine Bi2Se3 are comprehensively investigated by different material characterization techniques. The results demonstrate the successful in situ composite fabrication between the Bi2Se3, Ag and γ-MnOOH components. Besides, the present work introduces a systematic approach for the examination of electrical transport properties in Ohmic and non-Ohmic regimes over a wide temperature range. The results from the room temperature transport measurement exhibited that the nanocomposite demonstrated non-linearity after a certain current I0 (onset current), whereas Bi2Se3 was linear in the entire measured current range. An enhancement of the conductance was observed for Bi2Se3-AgMnOOH compared to the pure Bi2Se3 material, which is credited to the composite effect. The onset exponents xT (DC conductance) and xf (AC conductance) with phase-sensitive character demonstrate different values below and above 180 K separating two different phases with different conduction mechanisms. Also, flicker noise analysis established the correlation between the DC conductance in terms of Ohmic to non-Ohmic transition after the onset voltage V0. This transition phenomenon from Ohmic to non-Ohmic behaviour is explained from the structural point of view of the nanocomposite. The present investigation highlights the importance of using the bottom-up solution-phase strategy for the synthesis of high quality Bi2Se3-based nanocomposites for transport studies and their possible future applications.

Sutanu Das

Papers

Intercalation pseudocapacitance in Bi2Se3−MnO2 nanotube composite for high electrochemical energy storage

Redox-Guided Synthesis of Au–V2O5–MnO2 Nanoflower Composites with Enhanced Electrical Conductance for Supercapacitor Applications

Investigation of electrical transport properties in solution-processed Bi2Se3-AgMnOOH nanocomposite.