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As a critical component, high-performance separator is in urgent demand for the development of high-power lithium-ion battery (LIB). Herein, five commercial separators including cellulose, polyethylene terephthalate (PET), aramid nonwovens, and polypropylene (PP) and polypropylene/polypropylene (PP/PP) polyolefin membranes were investigated and used as high-power LIB separators. Due to the high porosity (70%), low air permeability, high electrolyte uptake and ionic conductivity (1.37 mS cm−1), excellent electrolyte wettability, and good heat resistance for cellulose separator, the corresponding LIBs exhibit the best comprehensive performance with low resistance, good rate capability of 91.8% retention at 10 C, long-term stability at 65 °C, and high capacity retention of 95.5% after 2000 cycles, indicating the promising application in LIBs with high power and long-term stability.

Inspired by biomineralization, we develop a facile synthesis route to obtain 3D porous foam-like Na3V2(PO4)3@C composites consisting of ultra-small Na3V2(PO4)3 particles in situ wrapped with carbon architecture derived from yeast as storing sodium cathode. 3D carbon architecture with high electrical conductivity is endowed with important effect on bio-restricting the aggregation of Na3V2(PO4)3 nanoparticles, improving Na+ diffusion coefficient. As a result, the Na3V2(PO4)3@C cathode shows good rate performance with 109 mAh g−1 and 44 mAh g−1 at 0.5 C and 20 C, respectively. Besides, the storage mechanism and structure evolution of Na3V2(PO4)3@C have been certified by ex situ XRD and electrochemical impedance spectroscopy. The unique biomineralization process enables to improve the electrochemical performances of Na3V2(PO4)3 by a facile self-organized process in a friendly environment. Therefore, biomineralization is a promising way to prepare high-performance cathode material with mesoporous structure for batteries.

Lithium-ion capacitors (LICs) are an optimal candidate to bridge the gap between lithium-ion battery and conventional supercapacitors as the promising electrochemical energy storage devices with fast charging-discharging capability and long cycle life. A three-electrode LIC pouch cell is fabricated employing an electrochemically driven lithium pre-doping method. Active materials of cathode and anode of LIC cells are activated carbon and pre-lithiated carbon, respectively. The electrochemical performances and capacity fading behaviors of LICs in an operating potential range of 2.2–3.8 V have been analyzed. The most direct influencing factor to LIC cycle performance is pointed at the developed capacity originated from the effective application of cathode material during the charge storage process. It was deeply discovered that the determined key to properties in a LIC system refers to the type of anode material and anode potential swing. Capacity fading of LICs upon cycling is proposed to be caused by the lapse of lithium stored in anode by dV/dQ analysis and an increase of internal resistance mainly emphasized on the structure difference through EIS characterization. As the energy density is increased to reach 63.05 Wh kg−1 based on the weight of both cathode and anode active materials and concurrently the initial capacitance is retained up to 96.33% after 5000 cycles at 8 C, HC as an anode material shows the prominent electrochemical performance.

A silicon oxycarbide (SiOC) material was prepared by high-temperature pyrolysis of polyvinyl alcohol (PVA)-modified polysiloxane using phenyltriethoxysilane (PhTES) as raw material and PVA as a composition-modifying additive via sol–gel route, and characterized as an anode material for Li-ion batteries. This modified SiOC material demonstrates superior electrochemical performance to the pristine SiOC material in terms of reversible specific capacity, rate performance, and cycling stability, especially for the significantly improved cycling stability. Long-term cycling test result shows that the initial reversible charge specific capacity delivered at the current density of 100 mA g−1 is 515.2 mAh g−1. After 150 cycles, a capacity of 504.6 mAh g−1 is still remained, giving capacity retention of 97.9%. The improved electrochemical performance is attributed to the increased carbon content and enhanced electrical conductivity as well as the changed morphology of the modified material due to the composition modification of the polymer pre-ceramics.

A Co3O4/vapor-grown carbon fiber (VGCF) hybrid material is prepared by a facile approach, namely, via liquid-phase carbonate precipitation followed by thermal decomposition of the precipitate at 380 °C for 2 h in argon gas flow. The material is characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller specific surface area analysis, and carbon elemental analysis. The Co3O4 in the hybrid material exhibits the morphology of porous submicron secondary particles which are self assembled from enormous cubic-phase crystalline Co3O4 nanograins. The electrochemical performance of the hybrid as a high-capacity conversion-type anode material for lithium-ion batteries is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/charge methods. The hybrid material demonstrates high specific capacity, good rate capability, and good long-term cyclability, which are far superior to those of the pristine Co3O4 material prepared under similar conditions. For example, the reversible charge capacities of the hybrid can reach 1100–1150 mAh g−1 at a lower current density of 0.1 or 0.2 A g−1 and remain 600 mAh g−1 at the high current density of 5 A g−1. After 300 cycles at 0.5 A g−1, a high charge capacity of 850 mAh g−1 is retained. The enhanced electrochemical performance is attributed to the incorporated VGCFs as well as the porous structure and the smaller nanograins of the Co3O4 active material.

Fruit waste pomelo peel was employed as raw material to prepare a highly porous and partial graphitized carbon material (pomelo peel-derived carbon (PPDC)). Se/PPDC nanocomposite was fabricated through ball milling and melt diffusion of selenium and PPDC mixture powder. The characterization results showed that selenium with 47 % loading content were confined homogenously in the small pores (

Olivine-type pristine LiMnPO4 and nickel-substituted LiNi0.05Mn0.95PO4 electrode materials were synthesized via a sol–gel route, and characterized by X-ray diffraction (XRD), transmission electron microscopy, and X-ray fluorescence analysis techniques. Their electrochemical properties in 2 M Li2SO4 aqueous solution were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge methods. Furthermore, X-ray absorption near edge structure analysis and XRD technique were employed to study the structural change of the pristine LiMnPO4 during the first charge/discharge cycle and the first-stage repeated charge/discharge activation cycles (increase in discharge capacity with increasing cycle number). The LiMnPO4-based electrodes were found to undergo a first-stage activation process with gradual increase in discharge capacity prior to capacity degradation in the experimental condition. Partial nickel substitution for manganese in LiMnPO4 can enhance the charge transfer reaction kinetics, and thereby increase the specific capacity of the LiMnPO4-based electrode.