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

Abstract

Porous hollow structure of the electrode materials can enlarge the surface area in contact with the electrolyte, accelerating the transport of ions and electrons during redox reaction to enhance electrochemical...

Engineering Rich-Cation Vacancies in CuCo2O4 Hollow Spheres with a Large Surface Area Derived from a Template-Free Approach for Ultrahigh Capacity and High-Energy Density Supercapacitors

“…Additionally, the CCOHS was shown to have a superior capacity compared to numerous previously reported findings regarding CuCo 2 O 4 -based electrode materials (mostly @1 A g –1 ), for instance, CuCo 2 O 4 microspheres (109.4 C g –1 ), CuCo 2 O 4 nanoparticles (229.5 C g –1 @2 A g –1 ), bundle-like CuCo 2 O 4 (303.22 C g –1 ), honeysuckle-like CuCo 2 O 4 /CuO composites (350.69 C g –1 ), flower-like CuCo 2 O 4 (466.4 C g –1 ), chestnut-like CuCo 2 O 4 /NF (502.4 C g –1 ), CuCo 2 S 4 /CuCo 2 O 4 nanoflowers (599.9 C g –1 ), CuCo 2 O 4 @MnMoO 4 core–shell nanosheets (663.8 C g –1 ), and CuCo 2 O 4 /MnCo 2 O 4 //graphene/Ni foam (860.4 C g –1 ) . Also, the CCOHS showed high specific capacity compared with the background of various hollow structured battery-type electrode materials summarized in Table S2 such as hollow nanosword-like CuCo 2 O 4 /NF (717 C g –1 ), NiS hollow microspheres (983.16 C g –1 ), Ni x Co 3– x O 4 hollow particles (597.96 C g –1 ), and NiCo 2 Se 4 (943.2 C g –1 ) . The CCOHS electrode also demonstrated 92% initial capacity retention with a current density increase of 10 times and 82% initial capacity retention with a current density increase of 20 times.…”

“…22 Also, the CCOHS showed high specific capacity compared with the background of various hollow structured battery-type electrode materials summarized in Table S2 such as hollow nanosword-like CuCo 2 O 4 /NF (717 C g −1 ), 19 NiS hollow microspheres (983.16 C g −1 ), 53 Ni x Co 3−x O 4 hollow particles (597.96 C g −1 ), 54 and NiCo 2 Se 4 (943.2 C g −1 ). 55 The CCOHS electrode also demonstrated 92% initial capacity retention with a current density increase of 10 times and 82% initial capacity retention with a current density increase of 20 times. These results demonstrate the excellent rate performance of the CCOHS electrode.…”

Coaxial nickel cobalt selenide/nitrogen-doped carbon nanotube array as a three-dimensional self-supported electrode for electrochemical energy storage

“…Even when the discharge current is increased to 20 mA cm −2 , the cell still exports a capacity of 1.0 C cm −2 (0.3 mA h cm −2 and 114.8 C g −1 ) and 12.5 C cm −3 . The capacity is comparable to, if not better than, those of previously reported nickel cobalt selenide-based energy storage devices including (Ni, Co) 0.85 Se//porous graphene (0.95 C cm −2 at 1 mA cm −2 ), 50 (Ni 0.1 Co 0.9 ) 9 S 8 @NF//rGO@NF (42.6 C g −1 at 0.2 A g −1 ), 20 H–NiCoSe 2 //AC (168 C g −1 at 0.2 A g −1 ), 51 CoNiSe 2 /CoNiSe 2 //CoNiO 2 /CoNiO 2 (16.2 C cm −3 at 50.9 mA cm −3 ), 52 (Ni, Co)Se 2 /NiCo-LDH//porous carbon (163.2 C g −1 at 2 A g −1 ), 53 NiCo 2 Se 4 //BiSe (308.7 C g −1 at 2 A g −1 ), 54 Ni 4.5 Co 4.5 -Se/NPCC//Fe 3 C/CF (113.7 C g −1 at 1 A g −1 ), 55 NiSe 2 /CoSe 2 //N, S-rGO (257.5 C g −1 at 0.5 A g −1 ), 56 etc. The long-term durability is examined via the repetitive charge–discharge process at 10 mA cm −2 .…”

Smart Textile Flexible MnCo2O4 Electrodes: Urea Surface Modification for Improved Electrochemical Functionality

“…Figure 9c depicts the MnCo 2 O 4 electrode's Nyquist plot, where the straight line in lower frequency areas shows electrolyte diffusion. The intercept on the x-axis indicates the series resistance (R s ) at higher frequency areas, which occurs owing to the resistance of the electrode material, electrolyte, and electrode-electrolyte interface [46][47][48][49][50]. The charge transfer resistance (R ct ) is represented by the semicircle diameter in EIS.…”