Assembling porous carbon-coated TiO2(B)/anatase nanosheets on reduced graphene oxide for high performance lithium-ion batteries

Novel porous carbon-coated mixed-phase porous TiO2 (TiO2(B)/anatase) nanosheets/reduced graphene oxide composites (TiO2@C/RGO) are successfully prepared through a facile one-pot solvothermal process followed by subsequent heat treatment in H-2/Ar. The as-formed composites have a hierarchical porous structure, involving an average pore size of 28.56 nm, a large pore volume of 0.589 cm(3) g(-1) and a desired surface area (136.19 m(2) g(-1)). When used as an anode material in LIBs, TiO2@C/RGO exhibits stable cycling performance with a reversible capacity of 272.9 mAh g(-1) (with the second capacity retention of 151.1%) after 500 cycles at a current density of 100 mA g(-1), much higher than that of TiO2@C (177.6 mAh g(-1), 123.9% of the discharge capacity in second cycle) and TiO2 (75.1 mAh g(-1), corresponding to 96.5% of the original capacity). More impressively, the capacity of TiO2@C/RGO can reach 158.6 mAh g(-1) after 500 cycles even at 800 mA g(-1) with Coulombic efficiency above 99.0%. The superior electrochemical performance of TiO2@C/RGO may be attributed to its unique 3D hierarchical porous structures, the existence of carbon, large surface area and extremely reduced diffusion length. (C) 2015 Elsevier Ltd. All rights reserved.