LiBr, as a representative of highly soluble electrochemically active materials, is fixed in nanopores of conductive carbon black (CCB). The Li/LiBr–CCB battery exhibits excellent high-rate capability to avoid slow solid-phase diffusion of Li ions in traditional solid cathode materials. The success will broaden the range of alternative materials for cathodes in LIBs and make them capable of providing both high power density and energy density.

Enhanced initial coulombic efficiency (above 90%) of Li1.14Ni0.16Co0.08Mn0.57O2 (LMO) cathode materials are achieved by utilizing a NaCl molten-salt method. Anaerobic environment can be controlled via adjusting the weight ratio of LMO and NaCl molten-salt. The morphology and structure of all samples are detected by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). The modified samples have smaller particle sizes and abundant mesopores, compared with the pristine LMO sample. The change of crystal parameters, XPS analysis and HRTEM images demonstrate the effect of anaerobic environment offered by NaCl molten-salt on the structure of LMO material. More oxygen vacancies could exist in the modified LMO materials due to the anterobic environment offered by a lot of NaCl molten-salt. It should be responsible for the enhanced initial coulombic efficiency. The higher reversible capacities mainly come from smaller particle size and abundant mesopores of the modified LMO samples, in which the utilization ratio of active mass is improved due to the shortened diffusion length for Li ions. A tiny spinel phase generates in the modified samples controlled by the amount of NaCl additive. The excellent cycling stability and improved rate capacity of the modified materials are also achieved due to its good thermal stability and the 3D structure of the spinel phase. These results give a new insight into preparing lithium-rich cathode materials with high initial coulombic efficiency as well as superior performance for advanced lithium-ion batteries.High initial coulombic efficiency (above 90%) and enhanced cyclic stability of the modified LMO samples are achieved by controlling the reaction medium via a simple and facile molten-salt route.

An advanced anode material for lithium ion batteries, amorphous red phosphorous/active carbon composite (P/AC) with a high P content of 60.0 (wt.%), is prepared via a vaporization adsorption method. In the composite, amorphous red phosphorous is mainly loaded into the micropores of the AC matrix. The P/AC composite delivers an excellent capacity up to about 1550 mAh g −1 that is calculated on the basis of composite weight. The high capacity means that approximate 3 electrons are involved in the electrode reaction. At the same time, the P/AC composite exhibits a good cyclability with a capacity retention ratio of 83.6% after 50 cycles. Furthermore, the coulombic efficiency maintains above 97.5% in all the cycles except for the first cycle (76.1%). During the initial cycle, the lithiated and delithiated P/AC anode are further investigated. The formation of SEI film in the initial active process is confirmed. The high and stable electrochemical performance of P/AC composite benefits from the nanoscale of active mass P particles and its homogeneous dispersion onto the conductive AC substrate.

Pristine Li[Li0.17Ni0.2Co0.05Mn0.58]O2 (LNCM) and Li[Li0.17Ni0.2Co0.05Mn0.58−xAlx]O2−0.5x (x = 0.01, 0.02 and 0.04) (LNCMA) as Li-rich cathode materials for lithium ion batteries were synthesized via a sol–gel route. Inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the composition, structure and morphology of the LNCM and LNCMA samples. The homogeneous dispersion of the element Al in the LNCMA samples was confirmed using energy dispersive spectroscopic (EDS) mapping. Compared with LNCM, the larger crystal cell volume of LNCMA was verified by XRD and TEM analysis. A blue shift of O1s and Mn2p peaks in the A2 sample was observed via XPS, demonstrating the partial substitution of Al3+ for Mn4+ ions. The electrochemical properties are examined by means of cyclic voltammetry and charge/discharge tests. In general, the Al-substituted samples exhibit a better electrochemical performance. Especially for the A2 sample, it presents an enhanced initial discharge capacity of ∼300 mA h g−1, accompanied with the better initial coulombic efficiency of 90.9%. For 5 C rate, the A2 sample delivers a higher discharge capacity of 168.9 mA h g−1 in the initial cycle and 156.5 mA h g−1 after 150 cycles, while for the pristine sample it is 126.5 and 98.8 mA h g−1, respectively. The excellent electrochemical performance of the Al-substituted samples could be ascribed to the enlarged cell volume and improved structural stability resulting from the partial Al substitution.

Li-rich layered oxides Li(Li0.17Ni0.2Co0.05Mn0.58)O2 (LNCMO) and LiAlO2-coated samples were prepared by sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The LiAlO2-coated sample shows good electrochemical performance compared with that of the pristine sample such as initial coulombic efficiency, cyclic performance, and rate capability. The LiAlO2-coated sample can deliver high initial discharge capacities of 268.2 and 191.9 mAh g−1 at 0.1 and 1 C rates with a capacity retention rate of 91.7 and 91.3 % after about 70 and 140 cycles, respectively. Meanwhile, it shows outstanding high-rate capability cyclability with less than 5 % capacity fade after 70 cycles at 5 C rate. The electrochemical impedance spectra (EIS) data indicate that the LiAlO2 coating can remarkably suppress the increase of the charge transfer resistance and restrain the structure change of LNCMO during the cycles which should make a great contribution to the high-rate capability of LiAlO2-coated LNCMO material.

An in situ sulfur deposition route has been developed for synthesizing sulfur–carbon composites as cathode materials for lithium–sulfur batteries. This facile synthesis method involves the precipitation of elemental sulfur into the nanopores of conductive carbon black (CCB). The microstructure and morphology of the composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that most of the sulfur in the amorphous phase is chemically well-dispersed in the nanopores of the CCB. The sulfur content in the composites is confirmed using thermogravimetry analysis (TGA). The S–CCB composites with different sulfur content (52 wt%, 56 wt% and 62 wt%) deliver remarkably high initial capacities of up to 1534.6, 1357.4 and 1185.9 mA h g−1 at the current density of 160 mA g−1, respectively. Correspondingly, they maintain stable capacities of 1012.2, 957.9 and 798.6 mA h g−1 with the capacity retention of over 75.1% after 100 cycles, exhibiting excellent cycle stability. The electrochemical reaction mechanism for the lithium–sulfur batteries during the discharge process is investigated by electrochemical impedance spectroscopy (EIS). The significantly improved electrochemical performance of the S–CCB composite is attributed to the carbon-wrapped sulfur structure, which suppresses the loss of active material during charging–discharging and the restrained migration of the polysulfide ions to the anode. This facile in situ sulfur deposition method represents a low-cost approach to obtain high performance sulfur–carbon composite cathodes for rechargeable lithium–sulfur batteries.

In this work, Lithium rich layered oxide Li1.17Ni0.2Co0.05Mn0.58O2 (LNCMO) is prepared and coated with Li3V2(PO4)3 (LVP) by a chemical deposition method. The surface modification with LVP is introduced into Li-rich layered oxides LNCMO for the first time. After 100 cycles of charging and discharging at various rates, the Li3V2(PO4)3-coated Li1.17Ni0.2Co0.05Mn0.58O2 (LVP-coated LNCMO) (5 wt%) still provides a large capacity of 261.4 mAh g-1, much higher than the pristine LNCMO (211.5 mAh g-1). At 5 C rate, the LVP-coated LNCMO exhibits a stable cyclic capacity of 153.4 mAh g-1, higher than 114.1 mAh g-1 of the pristine LNCMO. The electrochemical impedance spectroscopy (EIS) analysis demonstrates the LVP coating layer can suppress interaction between the cathode surface and the electrolyte and enhance the kinetics of lithium-ion diffusion, contributing to the stable cyclic performance with more cyclic capacity as well as at the high current density.

A rechargeable lithium/iodine battery using commercial organic electrolyte, composed of iodine–conductive carbon black composite as cathode and metallic lithium as anode, is first proposed in this work. The fabricated lithium/iodine battery presents superior high-rate capability and good reversibility based on the contributions from both the capacitive characteristics of conductive carbon black, and the redox capacity of active iodine in the composite.

Ferrate is considered to be a potential cathode material for high-energy batteries, due to its high capacity based on three-electron transfer in electrochemical reactions. In this work, high-purity potassium ferrate (K2FeO4) was synthesized by a direct hypochlorite oxidation method. X-ray diffraction (XRD) and a charge-coupled device (CCD) were used to characterize the structure of the K2FeO4 as well as the channels for intercalation–deintercalation of Li ions. The one-dimension channel was observed in the direction of the a and b axes in the unit cell, with a radius 0.93 Å, which is beneficial for Li ion (radius = 0.76 Å) intercalation and deintercalation in K2FeO4. The experimental super-iron Li ion battery was assembled with 1 M LiPF6 organic electrolyte (PC:EC:DMC = 1:3:6, v/v), a K2FeO4 cathode, and a metal lithium anode. The electrochemical performance of the K2FeO4 cathode was evaluated by a galvanostatic method and cyclic voltammetry (CV) in the potential range of 4.3–0.5 V at room temperature. It was demonstrated that one Li ion intercalates into the lattice of the K2FeO4 cathode along the channels of the a and b axes of the K2FeO4 unit cell, followed by a two-Li ion intercalation of isotropy in the initial discharge process. Amorphization of the K2FeO4 cathode is the main cause of its electrochemical performance decay.

An in situ sulfur deposition route has been developed for synthesizing sulfur–carbon composites as cathode materials for lithium–sulfur batteries. This facile synthesis method involves the precipitation of elemental sulfur into the nanopores of conductive carbon black (CCB). The microstructure and morphology of the composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that most of the sulfur in the amorphous phase is chemically well-dispersed in the nanopores of the CCB. The sulfur content in the composites is confirmed using thermogravimetry analysis (TGA). The S–CCB composites with different sulfur content (52 wt%, 56 wt% and 62 wt%) deliver remarkably high initial capacities of up to 1534.6, 1357.4 and 1185.9 mA h g−1 at the current density of 160 mA g−1, respectively. Correspondingly, they maintain stable capacities of 1012.2, 957.9 and 798.6 mA h g−1 with the capacity retention of over 75.1% after 100 cycles, exhibiting excellent cycle stability. The electrochemical reaction mechanism for the lithium–sulfur batteries during the discharge process is investigated by electrochemical impedance spectroscopy (EIS). The significantly improved electrochemical performance of the S–CCB composite is attributed to the carbon-wrapped sulfur structure, which suppresses the loss of active material during charging–discharging and the restrained migration of the polysulfide ions to the anode. This facile in situ sulfur deposition method represents a low-cost approach to obtain high performance sulfur–carbon composite cathodes for rechargeable lithium–sulfur batteries.

LiBr, as a representative of highly soluble electrochemically active materials, is fixed in nanopores of conductive carbon black (CCB). The Li/LiBr–CCB battery exhibits excellent high-rate capability to avoid slow solid-phase diffusion of Li ions in traditional solid cathode materials. The success will broaden the range of alternative materials for cathodes in LIBs and make them capable of providing both high power density and energy density.