Fusing semiconductor and nonmetal into a high conductive wide-range solid solution alloy for Li-ion batteries

•The semiconductor Ge and nonmetal red P enable to form a metallic-conductive GexP60-x solid solution alloy rather than metal phophide, which is in contradictory to the conventional view.•The GexP60-x alloy possesses black-phosphorus-like layered structure, contributing ultrahigh conductivity in contrast to general semi-conductive metal phosphides.•The GexP60-x undergoes a gentle alloy-type reaction rather than the chemical-bond-breaking conversion type reaction that took place in normal metal phosphides.•The GexP60-x alloy exhibits large reversible capacity with ultrahigh initial coulombic efficiency (92%) and suitable discharge plateau for fast charging batteries.