Synthesis of Mesoporous Germanium Phosphide Microspheres for High-Performance Lithium-Ion and Sodium-Ion Battery Anodes

Germanium phosphide is a potential anode material because of its high theoretical capacity and incredible rate capability on lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, the huge volume change that occurs while germanium phosphide is converted to Na3P or Li3P directly leads to poor cyclability and limits further applications. Herein, mesoporous germanium phosphide (MGePx) microspheres with diameter size ranging from 0.5 to1.5 mu m were first prepared by a one-step and template-free approach. MGePx microspheres were composed of nano-particles of around 10 nm with a narrow distribution of pore sizes of around 4 nm. The MGePx possessed superior features in LIBs/SIBs since it shortens the diffusion path of the energy carrier and provides the buffer space for the transport of Li/Na ions. MGePx showed attractive electrochemical properties as a potential anode candidate, such as a high first-cycle Coulombic efficiency of 82.63%, high reversible capacity (1400 mAhg(-1) after 150 cycles at 0.2C), excellent ultrahigh rate capacity (370 mA h g(-1)at 72 A g(-1),40 C), and stable cycling performance (450 cycles at 1 C) in the LIBs and high reversible capacity (704 mAh g(-1 )after 100 cycles at 0.2C) and stable cycling performance (200 cycles at 0.6C) in SIBs.