NiCo₂O₄ Hexagonal Nanoplates/Cornstalk-Derived Porous Carbon Composites for High-Performance Supercapacitor Electrodes

Abstract

Because of the ever-growing concern on fossil energy depletion and ecological environment devastation, the exploitation of biomass-based energy storage devices has been an imperative trend. Here, the one-step carbonization process plus hydrothermal method is proposed to prepare the composite of NiCo2O4 hexagonal nanoplates and three-dimensional porous carbon using cornstalk as the precursor, which can effectively enhance the electrochemical properties of supercapacitors. Compared with the bare cornstalk-derived porous carbon (CSPC) or single NiCo2O4 nanoplates, the as-prepared composite exhibits high specific capacitance and long cycle life, which can be ascribed to the integration of the merits of CSPC with a highly conductive pore-rich structure and NiCo2O4 with high energy density, good redox property, and short ion transport channel. The specific capacitance can reach 959.2 F·g–1 in 6 M KOH electrolyte at a current density of 0.5 A·g–1, and the capacitance retention is 93% at a current density of 20 A·g–1 over more than 5000 cycles, indicating that this composite can be considered as an outstanding electrode material for the development of high-performance supercapacitors.

Oxygen defect-mediated NiCo2O4 nanosheets as the electrode for pseudocapacitors with improved rate capability

“…Obviously, this ASC can deliver an energy density of 35.9 W h kg À1 at a power density of 200 W kg À1 , and even if the power density is increased to 6400 W kg À1 , the energy density can still be up to 22.4 W h kg À1 . Such excellent electrochemical properties of as-fabricated ASC are better than those reported on C-NiCo 2 O 4 //C (29.4 W h kg À1 , 253 W kg À1 ), 47 NiCo/NiO/NiCo 2 O 4 //AC (28.1 W h kg À1 , 415 W kg À1 ), 48 N-rGO/ NiCo 2 O 4 //N-rGO (14.9 W h kg À1 , 3500 W kg À1 ), 49 NiCo 2 O 4 /NiO// AC (31.4 W h kg À1 , 750 W kg À1 ), 50 NiCo 2 O 4 -NiCoO 2 /rGO//rGO (10.1 W h kg À1 , 4000 W kg À1 ), 51 NiCo 2 O 4 //AC (22.5 W h kg À1 , 800 W kg À1 ), 52 NiCo 2 O 4 /N-rGO//AC (20.1 W h kg À1 , 721 W kg À1 ). 53…”

MnO2 Nanoparticle‐Loaded Self‐Doped (N/O) Porous Carbon Derived from Orychophragmus Violaceus for Application as a High‐Performance Supercapacitor

“…C 1s of OPC can be deconvolved into three peaks located at 284.01 eV, 285.78 eV, 288.27 eV, which are related to the sp 2 C=C bond of graphitic carbon, CÀ N and C=O bands, where C=C bond is 56.68 % (Table S1). [22,23] C1s of OPC@MnO 2 32 can be divided into three peaks: C=C (283.75 eV), CÀ N (285.42 eV), and C=O (287.48 eV), with the C=C bond accounting for 68.83 % (Table S2). This reflects the dominance of C=C bond in the carbon matrix of OPC and OPC@MnO 2 32, reflecting the high degree of carbonization of the skeleton and is advantageous for the rapid transfer of electrons in the carbon skeleton.…”

“…Figure 4c and d show high‐resolution C 1s spectra of OPC and OPC@MnO 2 32. C 1s of OPC can be de‐convolved into three peaks located at 284.01 eV, 285.78 eV, 288.27 eV, which are related to the sp 2 C=C bond of graphitic carbon, C−N and C=O bands, where C=C bond is 56.68 % (Table S1) [22,23] . C1s of OPC@MnO 2 32 can be divided into three peaks: C=C (283.75 eV), C−N (285.42 eV), and C=O (287.48 eV), with the C=C bond accounting for 68.83 % (Table S2).…”

Two biomass material-derived self-doped (N/O) porous carbons from waste coriander and lilac with high specific surface areas and high capacitance for supercapacitors

“…First, C 1s of CPC-600 can be de-convoluted into four peaks located at 284.00 eV, 285.20 eV, 285.97 eV and 288.10 eV as shown in Fig. 3c, which are related to the sp 2 CQC bond of graphitic carbon, C-N, C-OH and CQO bands, 4,31 where the CQC bond is 57.61% (Table S3, ESI †). As shown in Fig.…”

“…Supercapacitors are a kind of green energy storage device with a high power density, fast charge-discharge rate, long cycle life and so on, and are an important means to achieve sustainable development. [3][4][5] According to the energy storage mechanism, supercapacitors can be divided into electric double-layer capacitors (EDLCs) and pseudocapacitors, of which EDLCs have a longer life, faster charge-discharge rate and higher power density due to their simple ion adsorption process at the electrode and electrolyte interface to store charge. 6 The performance of supercapacitors is closely related to the choice of electrode materials, which generally include three categories: metal compounds, conductive polymers and carbon materials, among which carbon materials include activated carbon (ACs), carbon fiber (CFs), carbon aerogels, graphene, carbon nanotubes (CNTs), etc.…”