Abstract
Phosphorus-rich transition metal phosphide CuP 2 nanowires were synthesized with high quality and high yield (60%) via the supercritical fluid-liquid-solid (SFLS) growth at 410 °C and 10.2 MPa. The obtained CuP 2 nanowires have a high aspect ratio and exhibit a single crystal structure of monoclinic CuP 2 without any impurity phase. CuP 2 nanowires have progressive improvement for semiconductors and energy storages compared with bulk CuP 2 . Being utilized for back-gate field effect transistor (FET) measurement, CuP 2 nanowires possess a p-type behavior intrinsically with an on/off ratio larger than 10 4 and its single nanowire electrical transport property exhibits a hole mobility of 147 cm 2 V -1 s -1 , representing the example of a CuP 2 transistor. In addition, CuP 2 nanowires can serve as an appealing anode material for a lithium-ion battery electrode. The discharge capacity remained at 945 mA h g -1 after 100 cycles, showing a good capacity retention of 88% based on the first discharge capacity. Even at a high rate of 6 C, the electrode still exhibited an outstanding result with a capacity of 600 mA h g -1 . Ex-situ transmission electron microscopy and CV tests demonstrate that the stability of capacity retention and remarkable rate capability of the CuP 2 nanowires electrode are attributed to the role of the metal phosphide conversion-type lithium storage mechanism. Finally, CuP 2 nanowire anodes and LiFePO 4 cathodes were assembled into pouch-type lithium batteries offering a capacity over 60 mA h. The full cell shows high capacity and stable capacity retention and can be used as an energy supply to operate electronic devices such as mobile phones and mini 4WD cars.