Electrochimica Acta, Vol.212, 950-957, 2016
Complex titanates Sr1-xPbxLi2Ti6O14 (0 <= x <= 1) as anode materials for high-performance lithium-ion batteries
With the Pb doping content at Sr-site increasing, a series of Sr1-xPbxLi2Ti6O14 (x = 0, 0.25, 0.50, 0.75, 1.0) are synthesized by a simple solid-state reaction. It is found that the reversible capacity and rate capability experience a parabolic course from SrLi2Ti6O14 to PbLi2Ti6O14. Among all the as-prepared samples, Sr0.5Pb0.5Li2Ti6O14 shows the best cycling and rate properties. It delivers an initial charge capacity of 163.2 mAh g(-1) at 100 mA g(-1) with the capacity retention of 96.08% after 100 cycles. In addition, it can also deliver a reversible capacity of 141.8 mAh g(-1) at 700 mA g(-1). The superior electrochemical properties of Sr0.5Pb0.5Li2Ti6O14 are attributed to the reduced charge transfer resistance and increased lithium-ion diffusion coefficient after doping. Besides, in-situ X-ray diffraction is also performed to investigate the lithium-ion insertion/extraction behaviors of SrLi2Ti6O14, Sr0.5Pb0.5Li2Ti6O14 and PbLi2Ti6O14. The observed results confirm that Sr0.5Pb0.5Li2Ti6O14 has good structural stability and reversibility for repeated lithium storage. (C) 2016 Elsevier Ltd. All rights reserved.