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Page 6 of 12 Zhang et al. Energy Mater 2024;4:400043 https://dx.doi.org/10.20517/energymater.2023.102

of a chemical bond between SiO and carbon, enhancing charge transfer and increasing structural stability.
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To accurately determine the relative ratios of SiO in the SiO /G/C composite, TGA results (SiO /G/C) were
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conducted [Supplementary Figure 6], revealing a SiO content of 72%.
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The lithium storage performance of three types of anodes, namely SiO /G/C, SiO /G, and SiO /C, was
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investigated to assess their efficacy of a dual-carbon network for SiO . Figure 3A reveals CV curves of the
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SiO /G/C anode for the initial five cycles, elucidating the charging and discharging reactions. The cathodic
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peaks observed at 0.01 and 0.17 V indicate alloy reactions between Li and Si, while the anodic peaks at 0.51,
0.18, and 0.33 V were attributed to the de-alloying of Li Si. The increasing CV area from the first to the
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fourth cycle suggests an activation process during cycling. Conversely, the remarkable similarity between
the fourth and fifth curves implies the potential stability of the SiO /G/C over several cycles [35,36] .
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Figure 3B illustrated voltage curves of the SiO /G/C anode about the first three charging/discharging cycles
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-1
in the range from 0.01 to 1.5 V at a smaller current density of 0.1 A·g . It delivers high initial discharging/
charging capacities of 2,617/1,674 mAh·g , respectively, delivering an unsatisfactory initial coulombic
-1
efficiency (ICE) of 64%. The phenomenon is attributed to irreversible formation of Li O and lithium
2
silicates, which could potentially be addressed by prelithiation technology .
[37]
Discharging capacities of SiO /G/C acquired by changing current densities are presented in Figure 3C and
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D, showcasing its superior rate capabilities compared to SiO /C and SiO /G. The discharging capacity of
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SiO /G/C was 1,482 mAh·g when working at a current density of 0.5 A·g . While at 6.0 A·g , it maintains a
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-1
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better capacity (347 mAh·g ), surpassing those common results of SiO /G and SiO /C when performed at
-1
x
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equivalent current densities. Remarkably, after 100 cycles of comparison, with the current density reverting
to 1.0 A·g , the discharge capacity of SiO /G/C recovers to 855 mAh·g , indicating satisfactory rate
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x
capability. The initial ICE was verified through the voltage variations of SiO /G and SiO /C (Supplementary
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Figures 7 and 8, respectively) at 0.1 A·g for the first charging or discharging time. Consequently, SiO /G
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and SiO /C demonstrated ICE values of 62.0% and 64.9%, respectively, indicating minimal changes in ICE
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despite the construction of the carbon network. Superior performance of the SiO /G/C anode is attributed
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to reinforced electronic/ionic conductivity and surface passivation facilitated by the dual-carbon network.
Figure 3E depicts the cycling performance of three electrode types: SiO /G/C, SiO /G, and SiO /C. Notably,
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SiO /G/C outperforms control groups at 1.5 A·g , sustaining an encouraging capacity of 675 mAh·g over
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300 cycles. This highlights the pivotal role of the dual-carbon network in enhancing the Li storage
+
performance of SiO /G/C as an anodic material compared to control groups. Moreover, a high areal
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-2
capacity of the SiO /G/C electrode, acquired at 2.0 mA·cm , of 1.67 mAh·cm exhibits consistent capacity
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x
retention over 100 cycles, even loaded about 2.2 mg·cm [Figure 3F], underscoring its promising potential
-2
for practical application. Long-term cycling performance of SiO /G/C [Figure 3G] was demonstrated.
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Following activation (0.2 A·g ) in the initial three cycles, SiO /G/C underwent cycling at 1.0 A·g for
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-1
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500 cycles, delivering a noteworthy lithium storage of approximately 700 mAh·g with a capacity retention
-1
of 78% (compared to the fourth cycle, 898 mAh·g ). This performance surpasses that of many recently
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reported SiO -based anodes for LIBs [Supplementary Table 1] [18,21,25,38-43] .
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The electrical resistivities of SiO /G/C, SiO /C, and SiO /G samples were analyzed to discern differences in
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the conductive mechanism [Figure 4A]. The detailed electrical resistivity data of SiO /G/C are provided in
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Supplementary Table 2. Results indicated that SiO /C and SiO /G exhibited higher electrical resistivities of
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0.129 and 0.151 Ω·cm, respectively, compared to 0.075 Ω·cm for SiO /G/C. Enhanced electrical conductivity
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of SiO /G/C can be attributed to as-prepared dual-carbon network, facilitating a higher electron transfer
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