Ultrathin NiCo2O4 nanosheets assembled on biomass-derived carbon microsheets with polydopamine for high-performance hybrid supercapacitors

Renewable biomass‐derived carbons for electrochemical capacitor applications

“…Hybrid capacitors like battery‐type capacitors are identified as a kind of device in which one electrode stores electric charge through battery‐type faradaic process, while the other electrode stores electric charge based on capacitive mechanism 9 . Generally, hybrid capacitors combine the advantages of high‐power density of EDLCs and high‐energy density of pseudocapacitors, 13–15 yielding outstanding comprehensive performances. However, the cycling stability of such devices still requires further strengthening 16,17 .…”

Carbon Transition‐metal Oxide Electrodes: Understanding the Role of Surface Engineering for High Energy Density Supercapacitors

“…[48][49][50] Yuan et al prepared all-solid-state SC using Mn-doped NiMoO 4 and reduced graphene oxide (rGO) composite by heating metal salts with GO at 160°C for 8 h as shown in Figure 1(a). [51] Oxygen functionalities on the GO anchored the metal salts by electrostatic attraction and promoted the growth [141] NiÀ Co hydroxide@rGO 180°C for 12 h L-ascorbic acid, KOH [142] CNT@NiÀ Co double hydroxide nanoneedles 220°C for 24 h Urea [143] Functional porous Carbon/NiO 100°C for 10 h, annealing at 900°C under N 2 CTAB, NH 4 OH [82] NiCo 2 O 4 /Carbon nanofiber 90°C for 4 h, calcination at 350°C under air HMTA [144] NiCo 2 O 4 @polydopamine modified poplar catkins 120°C for 6 h, annealing at 300°C under air HMTA, Citric acid trisodium salt [88] ZnFe 2 O 4 /N-modified Graphene 180°C for 12 h, annealing at 250°C - [145] Electrodeposition Fe 3 O 4 /NiO@rGO/hexagonal-Boron nitride metal ions electroprecipitated on rGO/h-BN then calcined at 500°C - [80] CNT-Fe 3 O 4 -rGO rGO deposited on CNTÀ Fe3O4 film by electrophoresis LiClO 4 electrolyte solution [146] Mn-doped NiCo-LDH coated porous carbon electropolymerization and annealing of PANI on carbon cloth, electrodeposition of metals Polyaniline (PANI) carbon source [57] CC/Carbon fibers/NiCo 2 O 4 NiCo 2 O 4 electrodeposited on CF pre-deposited on CC by CVD method - [147] NiOx-CNT-NiCo 2 O 4 NiCo NPs and CNT co-deposited on Ni foam by electrophoresis catalytic amount of Ni + 2 [89] CNT/NiCo 2 O 4 core-shell structure NiCo 2 O 4 electrodeposited on CNT pre-deposited on stainless steel foil - [90] 3D Ni foam/N-doped CNT/ NiCo 2 O 4 NSs NiCo 2 O 4 electrodeposited on N-CNT pre-deposited on Ni foam, then annealed at 300°c in air - [148] r-GO/MnO 2 electrodeposited on stainless steel, annealing at 300°C - [53] Physical mixing MnOx-Carbon dots-Graphene nanocomposites CDs-Graphene solution mixed with KMnO 4 at 75°C - [60] Mesoporous 3D NiCo 2 O 4 /MWCNT aerogels supercritical CO 2 drying of gel containing metal ions Epichlorohydrin gelation agent [72] Ni/CNT/MnO 2 MnO 2 on Ni fiber dip coated with CNT followed by drying and washing - [149] CdS-CoFe 2 O 4 @rGO nanohybrid pre-synthesized CdS-CoFe mixed with rGO solution and heated in oil bath NH 4 OH, Hydrazine [150] CuÀ MOF/rGO composite ultrasonic mixing o...…”

“…Benefiting from richer redox reactions from both Ni and Co ions, the spinel NiCo 2 O 4 offers better electrical conductivity and richer redox reactions than monometallic nickel or cobalt oxides. [87][88][89] Unfortunately, single nickel-based oxides often exhibit limited kinetics during the redox reaction due to low electrical conductivity or severe agglomeration resulting in inferior capacitance and poor rate performance.…”

Metal-Supported Biochar Catalysts for Sustainable Biorefinery, Electrocatalysis, and Energy Storage Applications: A Review

“…Then this material showed 1137.5 F g −1 (at 5 A g −1 ) and retained 90.3% of its capacitance after 5000 cycles, and when it was tested in an asymmetric supercapacitor, using activated carbon as negative electrode, achieved an elevated energy density of ≈31 Wh kg −1 (at 900 W kg −1 ). In addition, the carbonization of catkins from diverse tree plants to produce Ni/Co-biocarbons for supercapacitors has been reported twice [113,114]. Thus, Nan et al [113] decorated poplar catkins-derived C microsheets with NiCo 2 O 4 and polydopamine (PD) (Figure 6a), testing an asymmetric supercapacitor system (positive electrode: NiCo 2 O 4 /PD/C and negative electrode: PD/C) with excellent performance: 39.1 Wh kg −1 at the power density of 800 W kg −1 , high cycling stability with a 4.5% capacity loss after 5000 cycles, and a wide potential window of 0-1.6 V. The other work [114] reported the production of willow catkin-derived carbon microtubes with supported Ni-Co sulfides nanoparticles.…”