Nest-Like Molybdenum Diphosphide-Carbon Nanotube Nanocomposite for Lithium-Ion Storage

Abstract

Metal phosphides (MPs) with high theoretical capacity and fast kinetics are considered useful anode materials for lithium-ion batteries (LIBs). Phosphorus-rich MPs are more attractive than phosphorus-lean ones for the preparation of lithium battery anodes because the capacity of MPs is usually proportional to the content of the phosphorus component. In this work, we synthesized a nest-like molybdenum diphosphide-carbon nanotube (MoP2–CNT) nanocomposite for a high-capacity and long-term cycle-stable anode. Due to the nanoscale size and carbon nanotube cross-linking, the nest-like MoP2–CNT possessed a short diffusion path of lithium ions, a good conductive network, and a permeable buffer layer. As a result, after 500 cycles, the specific capacity reached 504.7 mA h g–1 at 1.0 A g–1 and 310.6 mA h g–1 at 4.0 A g–1. Superior electrochemical performances were also achieved at high-mass-loading MoP2–CNT electrodes. In addition, the full cell composed of the MoP2–CNT anode and LiCoO2 cathode also exhibited an energy density of 378.2 Wh kg–1 and excellent rate and cycling performances, indicating the potential application of the MoP2–CNT nanocomposite. The above superior electrochemical performances demonstrated that the phosphorus-rich composites were promising candidates for the preparation of a high-capacity LIB anode.

Diphosphorus Center Derived from Polyoxometalate for High-Energy Lithium Storage of MXene Nanosheets

“…The reaction current density, especially the oxidation current density, increases with the increase in the amount of PMA (as shown in Figure f–h), which is in accordance with the results of the charge and discharge curves. The reduction peak at 1.02 V is assigned to the lithiation process in the MoO 6 octahedron of Keggin structure polyoxometalate, and the oxidation peak at 1.44 V is assigned to the delithiation process. , The reduction peak at 0.73 V is assigned to the lithiation and conversion reaction of MoP 2 → Li 3 P, and the oxidation peak at 0.93 V corresponds to the delithiation of Li 3 P → Li x MoP 2 . In the second CV curve, the reaction current density of redox peaks for 0.05PMA@Ti 3 C 2 T x decreases, which is attributed to the capacity loss from an irreversible side reaction and the slight structure degradation.…”