TiPO and Expanded Graphite Nanocomposite as Anode Material for Aqueous Lithium-Ion Batteries.

This paper reports a facile sol-gel synthesis method to successfully prepare the TiPO/expanded graphite (EG) nanocomposite as an advanced anode material for aqueous lithium-ion batteries. The constructed TiPO nanocomposites (50-100 nm) are in situ encapsulated in the pore and layer structure of expanded graphite with good conductivity and high specific surface area. As a consequence, the resulting TiPO/EG electrode exhibits a reversible capacity of 66 mAh g at 0.1 A g with an appropriate potential of -0.6 V before hydrogen evolution in aqueous electrolytes, and also demonstrates greatly enhanced cycling stability with 75% capacity retention after 1000 cycles at the current density of 0.5 A g. A full cell consisting of TiPO/EG anode, LiMnO cathode, and 1 M LiSO electrolyte delivers a specific energy of 60 Wh kg calculated on the weight of both cathode and anode materials with an operational voltage of 1.4 V. It also exhibits superior rate capability and remarkable cycling performance with a capacity maintenance of 66% over 500 cycles at 0.2 A g and 61% at 1 A g over 2000 cycles.