3D hierarchical transition-metal sulfides deposited on MXene as binder-free electrode for high-performance supercapacitors

Abstract

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Comprehensive Insight into the Mechanism, Material Selection and Performance Evaluation of Supercapatteries

“…8 h, i) delivered a high energy density of 68.7 Wh kg −1 at a power density of 0.85 kW kg −1 . Likewise, Li et al [ 200 ] designed a supercapattery out of battery-type MXene-NiCo 2 S 4 over nickel foam (NF) substrate to form the positive electrode (MXene-NiCo 2 S 4 @NF) and activated carbon (AC) as a negative electrode material. The device worked in the potential window of 1.6 V and obtained maximum power density of 3.38 kW kg −1 .…”

Synthesis and Characterization of a NiCo2O4@NiCo2O4 Hierarchical Mesoporous Nanoflake Electrode for Supercapacitor Applications

“…As can be seen from Figure 3 a–d, NiCo-layered double hydroxides (LDH; before annealing) and bare NiCo 2 O 4 nanoflakes covered the surface of the substrate uniformly after the hydrothermal process. The creation of the nanoflake layer was based on non-homogeneous growth and nucleation, because of lower interfacial nucleation energy on the nickel foam [ 25 , 26 ]. The nanoflakes are very thin, causing complete employment of the active material.…”

“…The curve shapes show typically battery-type capacitive characteristics for the NiCo 2 O 4 @NiCo 2 O 4 electrode. The redox peaks were broad and weak, initiating from faradaic redox reactions associated with M-O/M-O-OH, where M signifies both ions of Co and Ni [ 26 , 28 ]. The current increased with an enhancement in the scan rate from 5 to 50 mV s −1 , whereas the CV curve shape remained unaffected, except for changes in peak positions.…”

“…In the low-frequency area, the NiCo 2 O 4 @NiCo 2 O 4 sample shows a shorter line and higher slope, signifying smaller variation in diffusion paths and a quicker OH – diffusion rate. The findings imply that the mixture of fast low electron transfer resistance and ion diffusion increases the electrochemical activities of the sample with the laminated structure [ 26 , 32 ]. The self-supporting nature of the sample, as well as the developed structures, permits quick ion–electron transport devoid of polymer binders and conductive additives, which usually increase the interfacial resistance [ 33 ].…”

Novel Aggregation-Induced Emission Materials/Cadmium Sulfide Composite Photocatalyst for Efficient Hydrogen Evolution in Absence of Sacrificial Reagent

“…As a valuable subgroup of semiconductive photocatalysts, transition-metal sulfides typically possess narrower band gaps than that of metal oxides, which makes them capable of various useful redox reactions under mild conditions, for instance, water splitting [ 1 , 2 ], high-energy-density supercapacitors [ 3 , 4 ], lithium-sulfur batteries [ 5 ], sodium ion battery anodes [ 6 ], for photovoltaic and photoelectrochemical devices [ 7 ]. To further explore the utilizations of the relevant photocatalysts, metal sulfides have been cooperated with many kinds of materials including metal oxides [ 8 ], carbon materials [ 9 , 10 ], and metal particles [ 11 ].…”