We demonstrate the synthesis of Ge@C three-dimensional porous particles (Ge@C TPP) via the decomposition of magnesium germanide (Mg₂Ge) and subsequent deposition of a carbon layer. Briefly, Ge TPP is first synthesized by the annealing of a Mg₂Ge precursor in air and a subsequent acid pickling process. Then, the carbon layer is deposited onto the Ge TPP by the pyrolysis of acetylene to form Ge@C TPP. When used as anode materials in lithium-ion batteries, the Ge@C TPP shows higher reversible capacity and better cycling performance than bulk Ge and bare Ge TPP. It is believed that the porous and core–shell structures can accommodate the volume change, give more lithiation sites, and stabilize the structure during the charge/discharge process, which may be responsible for the enhanced performance.