Hierarchical Hollow Microspheres Constructed by Carbon Skeleton Supported TiO2-x Few-Layer Nanosheets Enable High Rate Capability and Excellent Cycling Stability for Lithium Storage

Rational design and facile synthesis of TiO2 based hybrid electrodes with hierarchical microstructure have great advantages for exploration of advanced electrodes for lithium-ion batteries (LIBs). We design and synthesize hierarchical hollow microspheres with inner carbon skeleton supported outer TiO2-x few-layer nanosheets (C@TiO2-x). The "core-shell C@TiO2-x microspheres exhibit relatively high specific surface area and a remarkable electric conductivity (0.264 mu S cm(-1)). The lithium kinetics of C@TiO2-x microspheres is significantly improved due to synergistic effects of few-layer TiO2-x nanosheets and conductive carbon skeleton. The C@TiO2-x microspheres manifest an excellent reversible capacity of 323 mAh g(-1), together with an ultralong cycling lifetime that the capacity shows similar to 220 mAh g(-1) after 1000 cycles at 1.0 C. The C@TiO2-x microspheres also deliver a relatively high performance in rate capacity (108 mAh g(-1) at 20 C). When they are assembled into a hybrid lithium-ion capacitor, relatively high capacitance of 58 F g(-1) is achieved so that high power density reaches 14 kW kg(-1).