Abstract
In this work, complex spinel titanates Li2MTi3O8 (M = Zn, Cu, Zn0.5Cu0.5) have been synthesized by a simple solid state reaction route. Their crystal structures are described and verified by Rietveld refinement. Electrochemical results exhibit that Li2CuTi3O8 has a highest lithium storage capacity of 242 mA h g (1) and Li2ZnTi3O8 displays the lowest initial charge capacity of 190 mA h g (1) among all the three samples. However, both Li2CuTi3O8 and Li2ZnTi3O8 show poor capacity retention and low reversible capacity after 50 cycles. Li2Zn0.5Cu0.5Ti3O8 shows higher structural and cycling stability than that of Li2ZnTi3O8 and Li2CuTi3O8. As a result, Li2Zn0.5Cu0.5Ti3O8 can deliver a reversible capacity of 162 mA h g (1) after 50 cycles with capacity retention of 74%. (C) 2014 Elsevier B. V. All rights reserved.