Boosted lithium storage cycling stability of TiP2 by in-situ partial self-decomposition and nano-spatial confinement

Titanium phosphide (TiP 2 ) is particularly interesting due to its ability to form the stable Li–Ti–P ternary phase. However, TiP 2 faces the limitations in cyclic stability due to the volume change occurred by the destruction/recovery of the long-range cubic order Li–Ti–P phase, and unable to deliver high capacity. In this work, we propose the in-situ formation of electrochemically inactive TiP and phosphorus via partial decomposition of TiP 2 by ball milling process, achieving a multi-phase TiP 2 –TiP–P–C composite. On one hand, the decomposition-formed TiP effectively relieve the stress caused by the formation of Li x TiP 4 and LiP 3 . On the other hand, another decomposition-formed small-sized phosphorus significantly reduce its volume change during the lithiation/delithiation cycles for the overall capacity. Accordingly, the synthesized multi-phase TiP 2 –TiP–P–C with the above cooperative effects delivers a high capacity of 836.3 mAh g −1 at 0.2 A g −1 as high-performance Lithium-ion battery anode. In addition, a notable capacity retention of 81.4% is also achieved after 1000 cycles at 5 A g −1 . Furthermore, when paired with LiFePO 4 cathode in a full cell, the excellent specific capacity, cycling and rate performance can also be obtained. The rational design of TiP 2 –TiP–P–C will be beneficial towards the future development of metal-phosphide-phosphorous composite as LIB anode.