Sugarapple-like N-doped TiO2@carbon core-shell spheres as high-rate and long-life anode materials for lithium-ion batteries

In this work, sugarapple-like N-doped TiO2@N-doped carbon (NTiO2@NC) core-shell spheres have been synthesized with a facile and effective preparation process using polypyrrole (PPy) as carbon and nitrogen sources. Conductive N-doped carbon with slit pores uniformly coated on the TiO2 spheres surface. Benefiting from the N-doping and carbon shell, NTiO2@NC demonstrates superior long-term cycling stability and high-rate performance as anode materials for lithium ion batteries. Even tested at a current density of 5000 mA g(-1), the NTiO2@NC composites can deliver a reversible capacity of 232.7 mAh g(-1) after 2000 cycles. This new strategy may shed light on preparing metal oxides@NC core-shell composites for Li-ion batteries and other energy storage applications. (C) 2017 Elsevier B.V. All rights reserved.