High tap density microparticles of selenium-doped germanium as a high efficiency, stable cycling lithium-ion battery anode

Slurry cast electrodes with mm-sized Ge0.9Se0.1 particles cycle stably at similar to 800 mA h g(-1) with similar to 99.9% efficiency for 900 1C-rate cycles while electrodes with mm-size pure Ge particles lose 1/3rd of their capacity after five C/5 cycles. The difference is attributed to an inactive glassy Li-Se-Ge phase forming in the Ge active material of the Ge0.9Se0.1 particle.