“…However, the considerable capacities of Ge and CuO are generally accompanied by drastic volume change upon Li intercalation and deintercalation, thus causing the poor cycling performance (Liu et al, 2015;So et al, 2018). Great efforts have been made to solve the pulverization problem during the Li insertion and extraction process using nanomaterials such as nanoparticles (Hyojin et al, 2005;Mi-Hee et al, 2010;Yang et al, 2010), nanowires (Chan et al, 2008;Chockla et al, 2012;Yuan et al, 2012;Mullane et al, 2013), nanotubes (Chen et al, 2009;Cao et al, 2015;Liu et al, 2018a;Sun et al, 2018), and so on. For example, Li et al synthesized mesoporous and hollow Ge@C nanostructures via carbon coating and reduced the hollow ellipsoidal GeO 2 precursor into Ge.…”