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

作者：Zhou, Fengchen; Yang, Xu-Sheng^*; Liu, Jiangwen; Liu, Jun; Hu, Renzong; Ouyang, Liuzhang^*; Zhu, Min

来源：Journal of Power Sources, 2021, 485: 229337.

DOI：10.1016/j.jpowsour.2020.229337

• TiP2
• TiP
• In-situ formation
• Phase boundary
• Lithium-ion battery

Titanium phosphide (TiP2) is particularly interesting due to its ability to form the stable Li-Ti-P ternary phase. However, TiP2 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 TiP2 by ball milling process, achieving a multi-phase TiP2-TiP-P-C composite. On one hand, the decomposition-formed TiP effectively relieve the stress caused by the formation of LixTiP4 and LiP3. 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 TiP2-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 LiFePO4 cathode in a full cell, the excellent specific capacity, cycling and rate performance can also be obtained. The rational design of TiP2-TiP-P-C will be beneficial towards the future development of metal-phosphide-phosphorous composite as LIB anode.