The initial galvanostatic charging-discharging (GCD) curves of these Si-SiOx@Cs anodes at 0.1 A g -1 are shown in Fig. . Si-SiOx@C-5 anode exhibits lower initial coulombic efficiency (59.7%) and lower initial reversible capacity (552.6 mAh•g -1 ), while the other three anodes have close initial coulombic efficiency (69%) and similar initial reversible capacity (~1000 mAh•g -1 ). The irreversible loss is caused by the formation of the SEI layer. The rate performance of the four anodes at the current densities from 0.1 A•g -1 to 1.5 A•g -1 was also investigated (Fig. ). Si-SiOx@C-1.25 exhibits the highest capacity with the discharge capacity of 1116.2 mAh•g -1 , 970.3 mAh•g -1 , 748.6 mAh•g -1 , 551.3 mAh•g -1 and 451.5 mAh•g -1 at 0.1 A•g -1 , 0.2 A•g -1 , 0.5 A•g -1 , 1 A•g -1 and 1.5 A•g -1 , respectively. The discharge capacity of Si-SiOx@C-1.25 is fully recovered when the current density returns to 1 A•g -1 (585.3 mAh•g -1 ) and 0.1 A•g - 1 (1039 mAh•g -1 ) after cycling, showing good reversibility and superior capacity to the other three anodes. Longer cycling and performance are shown in Fig. under 0.2 A•g -1 . Initially, Si-SiOx@C, Si-SiOx@C-1.25 and Si-SiOx@C-2.5 show similar capacity (Fig. ), while low initial capacity of Si-SiOx@C-5 is caused by the lower silicon content inside. After several cycles, the capacity of Si-SiOx@C-1.25 and Si-SiOx@C-5 exhibit the increasing trend. Si-SiOx@C-1.25 exhibits the best cycling stability with a capacity retention of 74% at 630 mAh•g -1 after 300 cycles, while Si-SiOx@C degrades rapidly. GCD profiles of these four anodes after 10, 100, 200 and For Si-SiOx@C-5, more CNTs skeleton bring more pores inside the structure. With the continued volume expansion, more silicon should gradually be involved in the battery cycling, causing capacity increase (10 th and 100 th cycle in Fig. ). However, the low mechanical property (Fig. ) can't withstand the volume expansion, resulting in performance decay. Lower CNT content in Si-SiOx@C-2.5 with its denser structure improves the mechanical property in some degree. However, more CNT loading in Si-SiOx@C-2.5 means that more silicon particles would be covered, reducing the electrochemically reactive sites. Combined with the fact that the mechanical properties are not sufficient to withstand the volume expansion upon lithiation, Si-SiOx@C-2.5 exhibits a reduced performance fade compared to Si-SiOx@C and the capacity is close to Si-SiOx@C after 300 cycles. For Si-SiOx@C-1.25, the optimal CNT loading attaches more C-PDA-Si and SiOx@C particles onto the skeleton, offering more electrochemically active sites, with the capacity increasing in the first 50 cycles. The improved mechanical properties discussed previously (Fig. ) can withstand volume expansion during cycling, exhibiting the best cycling performance.