Rational design of hierarchically porous NiCo2O4 and Bi2O3 nanostructure: Anchored on 3D nitrogen doped carbonized melamine foam for flexible asymmetric supercapacitor

Asymmetric Supercapacitors Based on Hierarchically Nanoporous Carbon and ZnCo2O4 From a Single Biometallic Metal-Organic Frameworks (Zn/Co-MOF)

“…Batteries deliver high energy density and efficiency but relatively low power density determined by their energy storage mechanisms (Zhou et al, 2016 ; Chen et al, 2017 ; Wang et al, 2017 ; Sun et al, 2020 ). Meanwhile, SCs exhibit high power density and a long cycle life with low energy density (Shaibani et al, 2017 ; Cai et al, 2018 ; Shao et al, 2018 ; Yi et al, 2020 ). Consequently, the traditional single energy storage devices (batteries or SCs) cannot meet all the application requirements.…”

A self-templating scheme for the synthesis of NiCo2Se4 and BiSe hollow microspheres for high-energy density asymmetric supercapacitors

“…It can be found that although the material is purely BiSe, as characterized by XRD, there are a small amount of Bi-O bonds in the material. 40,42 The peak at 58.4 eV corresponds to SeO x , which is due to partial oxidation in air. 77…”

“…38,39 However, the low theoretical specific capacitance of carbonaceous materials restricts their energy density and further applications in supercapacitors. 40 Through the in-depth study of the negative materials, researchers found that some negative materials with high electrochemical performance and a suitable anode voltage window could be used as an alternative to carbon-based materials. For instance, Chavan et al reported Hematite α-Fe 2 O 3 thin films by spray pyrolysis from a non-aqueous medium, showing a specific capacitance of 451 F g −1 at 5 mV s −1 with a potential window ranging from −1.1 to 0.2 V. 41 Han et al prepared Bi 2 O 3 microrods with a carbon coat (Bi 2 O 3 @C) by a facile metalorganic framework (MOF)-derived strategy, which exhibited a high specific capacity of 1378 C g −1 at 0.5 A g −1 and excellent cycle life (93% after 4000 cycles).…”

Overview of transition metal-based composite materials for supercapacitor electrodes

“…As mentioned above, although transition metal oxides exhibit good electrochemical activities, they demonstrate inferior electrical conductivity and low rate capability. As such, bimetallic oxides such as M x N y O z with M/N being Zn, 66,67 Ni, [68][69][70] Mn, 71 Co, [72][73][74] or Cu 75 possess high specic capacitances due to their better electrical conductivity and higher active redox sites, as well as mechanical and thermal stability compared to their corresponding single component counterparts. For example, NiCo 2 O 4 , which exhibits two orders of magnitude higher electrical conductivity 76 than nickel or cobalt oxides, 44 and iron oxides 46 provides excellent electrochemical performance, therefore Fe-Co oxide (FeCo 2 O 4 ) should be an even better material since it offers richer redox reactions than the single components.…”