A nitrogen-doped graphene/sulfur composite was further modified with atomic layers of TiO2and used as the cathode of lithium–sulfur batteries, exhibiting superior cycling stability, good rate capability and high coulombic efficiency.

Direct carbon fuel cells offer highly efficient means of converting carbon from waste, biomass or coal to electricity producing an exhaust stream that is well-suited to CO 2 sequestration and, hence could underpin a new, clean carbon economy. If this technology is to contribute significantly to improving our impending global energy crisis, three aspects must first be addressed: competitive performance with extant fuel cell technologies, development of practical systems to handle available carbon resources and demonstration of sufficient durability, i.e. 40 000 hours minimum for system. In the present study, we demonstrate excellent performance from a hybrid direct carbon fuel cell based upon an yttriumstabilised zirconia electrolyte to use solid carbons as fuels directly. Good stability of the zirconia is observed during and after fuel cell testing and in corrosion tests under reducing conditions; however, significant intergrain erosion is observed under oxidising conditions. The carbon fuel chosen is a waste product, Medium Density Fibreboard, which is widely available and difficult to recycle. Cells exhibit excellent electrochemical performance at 750 C, with a maximum power density of 390 mW cm À2 using a lanthanum doped strontium manganite (LSM) cathode and 878 mW cm À2 using a lanthanum doped strontium cobalt (LSC) cathode under flowing air. This is comparable with current commercial Solid Oxide Fuel Cell and significantly in excess of commercial Molten Carbonate Fuel Cell (MCFC) performance. This hybrid direct carbon fuel cell therefore offers the clean utilisation of coal, waste and renewable carbon sources and hence merits development as a realistic alternative technology.

Li3VO4 is a potential anode for Li‐ion batteries owing to its safe discharge plateau and high capacity, but the reported reversible capacity is still far from its theoretical value (592 mAh g−1). Here, for the first time, a Li3VO4 anode is reported with reversible capacity approaching the theoretical value. Li3VO4 aggregates hybridized with carbon (Li3VO4/C) are first fabricated, and then dramatically transform into well dispersed Li3VO4 nanocrystals (NCs) anchoring on carbon nanoflakes (NFs) by electrochemical reconstruction. In the Li3VO4/C NC‐on‐NF structures, the small‐sized Li3VO4 NCs, the flexible carbon NFs, and the good dispersity provide high Li‐ion storage, electronic conductivity and stability, respectively. Resultingly, outstanding electrochemical performance of the Li3VO4/C is achieved with discharge and charge capacities of 542 and 541 mAh g−1 after 300 cycles at a specific current of 150 mA g−1. After 1000 cycles at a specific current of 2000 mA g−1, the discharge and charge capacities are maintained at 422 and 421 mAh g−1. When matching with a 4 V cathode, the specific energy density of the Li3VO4/C is 4.2 times of Li4Ti5O12 and 1.2 times of graphite, and the volumetric energy density is 3.2 times of Li4Ti5O12 and 1.4 times of graphite.