Supercapacitors have high power density and long cycling life but suffer from low energy density, which drives the search for better electrode materials. NiO/CeO2/GO ternary nanocomposites were prepared via a simple in situ assembly route that involved combining pre-synthesized NiO/CeO2 binary oxide and graphene oxide (GO) at three different mass ratios (1:1, 1:2, and 2:1). Structural and spectroscopic characterizations (XRD, FTIR and Raman) confirmed the successful incorporation of NiO and CeO2 nanoparticles on the GO sheets without any impurity phase. Thermal stability and elemental composition of the composite were verified through TGA/DTA and XPS. FE-SEM, TEM and AFM analyses revealed a porous and well-dispersed nanostructure with a primary average crystallite size of 13 nm and BET confirmed a hierarchical micro-mesoporous structure with a specific surface area of 122.92 m2 g−1. Among the studied ratios, the 2:1 NiO/CeO2/GO composite showed the best structural integrity and electrochemical performance, which was attributed to the synergistic effect between the pseudocapacitive redox activity of NiO/CeO2 (Ni2+/Ni3+ and Ce3+/Ce4+) and the conductive framework of GO. Electrochemical studies were performed in a three-electrode configuration in 3 M KOH and showed a specific capacitance of 290 F g− 1 at 1 A g− 1. Moreover, it showed excellent cycling stability with 96.88
Thermal thiol-yne click reactions between pentaerythritol tetrakis(3-mercaptopropionate) and α, ω-dipropiolate-terminated polyethylene glycols were carried out in propylene carbonate containing lithium bis(trifluoromethanesulfonyl)imide to obtain gel polymer electrolytes based on tetrafunctional cross-linked PEG network. Six polymer gel electrolytes were prepared with different PEG network content and cross-linking density (distance between cross-linking points). Ionic conductivity was dependent on the content of PEG network and the cross-linking density. The results of the Raman spectroscopy suggested coordination of lithium ions with the PEG chains of the network, which is considered to be a reason for conductivity decrease.
Prussian white is a promising cathode material for sodium-ion batteries (SIBs) due to its excellent chemical stability and low-cost resource advantage, but its electrochemical performance is severely degraded by crystalline defects such as coordinated water and Fe(CN)6 vacancies. To address this critical issue, this study proposes a novel solvothermal synthesis strategy using acetonitrile as the solvent instead of traditional aqueous systems, which effectively regulates the nucleation and growth kinetics ofthe material to reduce crystal defects. In contrast to Prussian white material prepared by the traditional co-precipitation method (MnHCF-2), the prepared manganese-based Prussian white (MnHCF- 1) exhibits high crystallinity, low water content (< 3 wt
Fe-NC catalysts were fabricated by electrospinning with tunable Fe/N precursor ratio and annealing temperature. These two parameters synergistically regulate the content of different nitrogen species. The results are consistent with FeN₄ being the dominant ORR active site, and its maximum content of 28
Sluggish Na+ transport kinetics and scarce electrochemically active interfaces represent critical bottlenecks restricting hard carbon anodes for sodium-ion batteries. In view of this, a dual-pronged strategy integrating morphology tailoring with defect engineering is proposed to endow rice husk-derived hard carbons with exceptional rate responsiveness and extended cyclability. Specifically, a 3D interconnected nanosheet-like porous carbon framework has been constructed via in situ desilication topological etching coupled with urea-assisted gas-blowing chemical activation. Microstructural characterizations and spectroscopic analyses confirm that the as-prepared carbon matrix possesses dilated microcrystalline interlayer spacing, hierarchical pore structures, and abundant defect centers dominated by edge-type pyridinic and pyrrolic nitrogen configurations. Consequently, the optimized RHC-N-3 electrode achieves a reversible capacity of 368.5 mAh g− 1 at 0.2 C, retaining 211.9 mAh g− 1 after 1000 cycles at a high rate of 5 C. Kinetic analysis coupled with potential-resolved capacity deconvolution elucidates an “adsorption-intercalation-pore filling” multi-stage mechanism, wherein abundant edge-nitrogen configurations facilitate fast surface-controlled capacitive storage in the sloping voltage region, while expanded lattice interlayers facilitate bulk solid-state transport in the plateau region. Furthermore, density functional theory (DFT) calculations confirm that nitrogen-doped vacancy defects significantly enhance Na adsorption affinity, elevate electronic state occupancy at the Fermi level, and lower the Na migration barrier from 0.561 eV to 0.111 eV. This study establishes a tailored defect-engineering paradigm for sustainable biomass-based carbon anodes while providing profound structure-property insights for designing high-power sodium energy storage devices.
