Rechargeable Li-iodine batteries are attractive electrochemical energy storage systems because iodine cathode provides the possibility of high energy density, wide abundance and low cost. However, the safety risk caused by low thermostability of iodine and the self-discharge reaction due to high solvency of iodine in aprotic solvent are target issues to be considered. Herein, we designed a room-temperature "solution-adsorption" method to prepare a thermostable iodine-carbon cathode by utilizing the strong adsorption of nanoporous carbon. Meanwhile, Li-iodine batteries constructed by the as-prepared cathode and ether-based electrolyte with the addition of LiNO3 showed negligible self-discharge reaction, high rate and long cycling performance. The reversible reactions of I2/LiI3 and LiI3/LiI in Li-iodine batteries were also proved with in situ Raman measurement. For the demonstration of application, soft-package batteries with Al-plastic film were assembled, displaying energy densities of 475 Wh/kg by mass of Li and iodine, and 136 Wh/kg by total mass of the battery. The use of nanoporous carbon to adsorb iodine at room-temperature represents a new and promising direction for realizing high-performance cathode for rechargeable Li-iodine batteries.

Sodium‐ion batteries (SIBs) are considered as promising candidates for large‐scale energy storage systems due to the wide availability and low cost of raw sodium resources. However, the heavier mass and larger radius of Na+ inevitably result in lower electrochemical kinetics and larger volume expansion of active materials than that of lighter and smaller Li+. To solve these problems, rational electrode design by integrating nanomaterials with graphene is an effective approach. In this review, the authors mainly focus on recent progress of graphene‐based nanomaterials for SIBs, including their design principle, preparation, characterization, and electrochemical performance. The important roles of graphene in graphene‐based inorganic and organic electrode materials are discussed in depth. In such composites, graphene can effectively enhance the electrical conductivity and mitigate volume change due to the robust and highly conductive networks formed by graphene. Moreover, the nanosized materials can enhance the reaction kinetics. Future research should focus on revealing the interaction mechanism between graphene and active materials, and improving the whole energy/power density, cycling stability, and the initial Coulombic efficiency of graphene‐based nanomaterials via elaborate design.

A facile one‐step spraying synthesis of MoS2/C microspheres and their enhanced electrochemical performance as anode of sodium‐ion batteries is reported. An aerosol spraying pyrolysis without any template is employed to synthesize MoS2/C microspheres, in which ultrathin MoS2 nanosheets (≈2 nm) with enlarged interlayers (≈0.64 nm) are homogeneously embedded in mesoporous carbon microspheres. The as‐synthesized mesoporous MoS2/C microspheres with 31 wt% carbon have been applied as an anode material for sodium ion batteries, demonstrating long cycling stability (390 mAh g−1 after 2500 cycles at 1.0 A g−1) and high rate capability (312 mAh g−1 at 10.0 A g−1 and 244 mAh g−1 at 20.0 A g−1). The superior electrochemical performance is due to the uniform distribution of ultrathin MoS2 nanosheets in mesoporous carbon frameworks. This kind of structure not only effectively improves the electronic and ionic transport through MoS2/C microspheres, but also minimizes the influence of pulverization and aggregation of MoS2 nanosheets during repeated sodiation and desodiation.

Developing high capacity and stable cathodes is a key to successful commercialization of aqueous Zn‐ion batteries (ZIBs). Pure layered V2O5 has a high theoretical capacity (585 mAh g−1), but it suffers severe capacity decay. Pre‐inserting cations into V2O5 can substantially stabilize the performance, but at an expense of lowered capacity. Here we show that an atomic layer deposition derived V2O5 can be an excellent ZIB cathode with high capacity and exceptional cycle stability at once. We report a rapid in situ on‐site transformation of V2O5 atomic layers into Zn3V2O7(OH)2⋅2 H2O (ZVO) nanoflake clusters, also a known Zn‐ion and proton intercalatable material. High concentration of reactive sites, strong bonding to the conductive substrate, nanosized thickness and binder‐free composition facilitate ionic transport and promote the best utilization of the active material. We also provide new insights into the V2O5‐dissolution mechanisms for different Zn‐salt aqueous electrolytes and their implications to the cycle stability.

In this paper, we report on the synthesis of micro-nanostructured CuO/C spheres by aerosol spray pyrolysis and their application as high-performance anodes in sodium-ion batteries. Micro-nanostructured CuO/C spheres with different CuO contents were synthesized through aerosol spray pyrolysis by adjusting the ratio of reactants and heat-treated by an oxidation process. The as-prepared CuO/C spheres show uniformly spherical morphology, in which CuO nanoparticles (∼10 nm) are homogeneously embedded in the carbon matrix (denoted as 10-CuO/C). The electrochemical performance of 10-CuO/C with a carbon weight of 44% was evaluated as the anode material for Na-ion batteries. It can deliver a capacity of 402 mA h g(-1) after 600 cycles at a current density of 200 mA g(-1). Furthermore, a capacity of 304 mA h g(-1) was obtained at a high current density of 2000 mA g(-1). The superior electrochemical performance of the micro-nanostructured CuO/C spheres leads to the enhancement of the electronic conductivity of the nanocomposite and the accommodation of the volume variation of CuO/C during charge/discharge cycling.