Template-Free Synthesis of Interconnected Hollow Carbon Nanospheres for High-Performance Anode Material in Lithium-Ion Batteries

The ever-increasing demand for rechargeable batteries in some newly emerging portable electronic devices, advanced medical devices, and in particular, electric vehicles and hybrid electric vehicles has sparked research efforts in developing lithium ion batteries (LIBs) with high storage capacity and excellent rate performance. [ 1 ] Graphite, the mainstay of anode materials for commercialized LIBs, could hardly meet the demand because of its low theoretical specifi c capacity (372 mAh g − 1 ), and thus provides ample opportunity for exploring alternative highperformance electrode materials. Si, Sn, SnO 2 and some transition metal oxides with ultra high theoretical capacities have been considered due to their special mechanism for Li storage. Unfortunately, huge volume change (in alloying electrodes) and large voltage hysteresis (in conversion electrodes) occurring in these materials during Li insertion and extraction handicap their extensive applications. [ 2 , 3 ] Therefore, continual research has been focused on designing new carbon-based anodes with high performances by virtue of their favorable stability and outstanding kinetics. Up to date, large number of novel carbonbased electrode materials with various microstructures have been investigated, such as carbon nanobeads, [ 4 ] nanotubes, [ 5 ]