All Transition Metal Selenide Composed High‐Energy Solid‐State Hybrid Supercapacitor

Abstract

Transition metal selenides (TMSs) have enthused snowballing research and industrial attention due to their exclusive conductivity and redox activity features, holding them as great candidates for emerging electrochemical devices. However, the real‐life utility of TMSs remains challenging owing to their convoluted synthesis process. Herein, a versatile in situ approach to design nanostructured TMSs for high‐energy solid‐state hybrid supercapacitors (HSCs) is demonstrated. Initially, the rose‐nanopetal‐like NiSe@Cu2Se (NiCuSe) positive electrode and FeSe nanoparticles negative electrode are directly anchored on Cu foam via in situ conversion reactions. The complementary potential windows of NiCuSe and FeSe electrodes in aqueous electrolytes associated with the excellent electrical conductivity results in superior electrochemical features. The solid‐state HSCs cell manages to work in a high voltage range of 0–1.6 V, delivers a high specific energy density of 87.6 Wh kg−1 at a specific power density of 914.3 W kg−1 and excellent cycle lifetime (91.3% over 10 000 cycles). The innovative insights and electrode design for high conductivity holds great pledge in inspiring material synthesis strategies. This work offers a feasible route to develop high‐energy battery‐type electrodes for next‐generation hybrid energy storage systems.

Coral-Inspired Hierarchical Structure Promotes a Win–Win on Mass Loading and Rate Capability: A Nickel–Cobalt–Zinc–Sulfide@Nickel–Cobalt Layered Double Hydroxide Electrode for a High-Performance Hybrid Supercapacitor

“…The k 1 v item refers to the contribution of the capacitive process to the total current, while the k 2 v item refers to the contribution of the diffusion process. The above formula can be reformulated as i 0.25em ( V ) / v 1 / 2 = k 1 v 1 / 2 + k 2 By plotting i / v 1/2 versus v 1/2 at different potentials, the values of k 1 and k 2 at different scan rates could be determined. , Based on the method, the proportions of the capacitive contribution of NiCoZn-LDH, NiCoZnS x , and NiCoZnS x @NiCo-LDH are calculated as 50.5, 35.4, and 32.5% at 1 mV s –1 , suggesting that the diffusion-controlled process is dominant in the total capacitance of NiCoZnS x and NiCoZnS x @NiCo-LDH. Moreover, the capacitive contribution of NiCoZnS x @NiCo-LDH increases from 32.5 to 76.0% with the scan rate increased from 1 to 20 mV s –1 .…”

Three-dimensional Ni0.85Se@ZnSe nanostructures on carbon cloth for flexible asymmetric battery-type supercapacitors

“…This may be due to the repeated charge–discharge process in alkaline KOH solution, which causes the surface of the electrode material to be corroded to form hydroxide. 45 The SEM images of the Ni 0.85 Se@ZnSe-10 CC electrode after 5000 cycles were further recorded to investigate structural changes of the electrode (Fig. S6†).…”

Cation-exchange and oxygen vacancies triggered capacity in hierarchical α-Ni1−xCuxMoO4@CC flexible electrodes for energy-storage applications

“…The rapid exploration of green and sustainable energy sources in energy technology has become of great importance due to the depletion of conventional fossil fuels. [1][2][3] Traditionally, supercapacitors are good candidates for fullling energy demands because of their advantage of high power density in various microdevices. 2 Although supercapacitors possess a long lifetime and excellent reversibility, their intermediate energy density features (oen <10 W h kg −1 ) are not competitive with batteries, restricting their practical applications.…”

“…[1][2][3] Traditionally, supercapacitors are good candidates for fullling energy demands because of their advantage of high power density in various microdevices. 2 Although supercapacitors possess a long lifetime and excellent reversibility, their intermediate energy density features (oen <10 W h kg −1 ) are not competitive with batteries, restricting their practical applications. 2,4 Flexible energy storage devices are becoming an alternative and mainstream for electrochemical storage equipment in modern society.…”

“…2 Although supercapacitors possess a long lifetime and excellent reversibility, their intermediate energy density features (oen <10 W h kg −1 ) are not competitive with batteries, restricting their practical applications. 2,4 Flexible energy storage devices are becoming an alternative and mainstream for electrochemical storage equipment in modern society. 5,6 Particularly, exible hybrid supercapacitors (FHSs) play a leading role as exible devices in wearable electronics, because of their good exibility, safety, and lightweight compared to other devices as well as long cycle life with impressive energy/power densities.…”