Sr0.95In0.05Li2Ti6O14: A high performance lithium host material.

Via Sr-site substitution, a series of Sr 0.95 M 0.05 Li 2 Ti 6 O 14 (M z+ = Na + , Cu 2+ , In 3+ ) are prepared as anode materials for lithium-ion batteries. It is found that the introduction of Na + , Cu 2+ or In 3+ into the crystal lattice can reduce the charge-transfer resistance and improve the lithium-ion diffusion coefficient of SrLi 2 Ti 6 O 14 . Especially for In 3+ -doping, it exhibits more obvious effect on these improvements. Furthermore, the substitution of Sr 2+ by In 3+ can also enhance the electronic conductivity via inducing a reduction of an equivalent number of Ti cations from Ti 4+ to Ti 3+ . As a result, Sr 0.95 In 0.05 Li 2 Ti 6 O 14 shows the best cycle and rate properties among all as-prepared samples. In addition, in-situ observation also proves that Sr 0.95 In 0.05 Li 2 Ti 6 O 14 is a zero-strain lithium storage compound during charge/discharge process. As a result, it delivers a lithium storage capacity of 136.4 mAh g −1 at 200 mA g −1 , 126.3 mAh g −1 at 400 mA g −1 and 121.0 mAh g −1 at 600 mA g −1 . In contrast, SrLi 2 Ti 6 O 14 only presents a charge capacity of 138.3 mAh g −1 at 200 mA g −1 , 120.3 mAh g −1 at 400 mA g −1 and 111.3 mAh g −1 at 600 mA g −1 . Therefore, In 3+ -doping is an effective method to enhance the electrochemical properties of SrLi 2 Ti 6 O 14 . [ABSTRACT FROM AUTHOR]