Efficient synthesis of Cu3P nanoparticles confined in 3D nitrogen-doped carbon networks as high performance anode for lithium/sodium-ion batteries

As a metal phosphide, copper phosphide (Cu3P) offers the advantages of low-cost, environmental friendliness, and excellent volumetric capacity. However, the development of Cu3P in lithium/sodium-ion batteries is limited by its poor conductivity, large volume change, and nano-crystal agglomeration. In this work, we prepared nano-scale Cu3P uniformly embedded in a nitrogen-doped three-dimensional (3D) porous carbon network (denoted as Cu3P/N-CN) through a simple and novel strategy of freeze-drying with NaCl crystals as template. The Cu3P nanoparticles effectively alleviated the physical strain generated during the charging and discharging processes and improved the utilization rate of the active material. Moreover, the 3D porous structure enhanced the conductivity, inhibited the agglomeration of the Cu3P nanoparticles, and facilitated the rapid diffusion of electrons/ions. The Cu3P/N-CN composite anode exhibited an outstanding rate capability (431.6 mAh g−1 at 3.0 A g−1), outstanding cyclic stability (752.3 mAh g−1 at 0.1 A g−1 over 100 cycles) for lithium storage, and excellent rate performance (220.0 mAh g−1 at 3.0 A g−1) and cycle performance (340.9 mAh g−1 at 0.1 A g−1 over 100 cycles) for sodium storage. This novel Cu3P/N-CN electrode thus has a promising application in energy storage technologies.