Improving the initial Coulombic efficiency of SiO anode materials for lithium ion batteries by carbon coating and prelithiation

Silicon monoxide (SiO) is a common high-capacity anode material for lithium-ion batteries (LIBs). However, its low initial Coulombic efficiency (ICE) hinders its development as anode material for LIBs. Here, we report a composite material (d-SiO/C/LSO) prepared by prelithiation of carbon coated disproportionated SiO (d-SiO/C) with lithium hydride (LiH), which has an ICE of 90.3 % and initial discharge capacity of 1465 mAh/g. Compared with the ICE (76.7 %) of SiO materials obtained by a single carbon coating process or the ICE (81.0 %) of SiO materials obtained by a single pre-lithiation process, the ICE of SiO materials obtained by the combination of the two processes has been greatly improved. Meanwhile, the carbon layer, and the partial lithium silicate phase between the carbon layer and SiO also have a favourable effect on the cycling performance of the SiO anode for LIBs. The NMC811||d-SiO/C/LSO full cell shows the capacity retention of 86.5 % after 100 cycles.