Fig. 1

Study of the chemical reaction. (a) Illustration of the experiment; (b) and (c) MS results of the electrolyte and Si after the reaction, respectively; (d) XRD data of Si after the reaction; (e) F1s spectrum results for Si@C after the reaction; TEM image of Si@C before (f) and after (g) reaction; (h) EDS Mapping of Si@C after reaction"

Fig. 2

The activation energy for the reactions of Si and Si@SiC with LiPF6"

Fig. 3

The proportion of side reaction in actual electrochemical process. (a) Cycling performance test; (b) The proportion of side reaction; (c) Capacity retention rate changing with time"

Fig. 4

Illustration of suppressing the side reaction"

Fig. 5

Inhibition of side reaction for Si@TiN. (a) MS results; (b) XPS results; (c) Capacity rate with different cycles; (d) Proportion of side reaction"

Fig. 6

EIS results of different cycles. (a) EIS data of Si@C after different cycles; (b) EIS data of Si@C after different cycles; (c) Comparison of diffusion coefficients of lithium ions"

Fig. 7

The Comparison of Si@C and Si@TiN after different cycles. (a) SEM image of fresh Si@C; (b) SEM image of Si@C after 5 cycles; (c) Top-view SEM image of fresh Si@C; (d) Top-view SEM image of Si@C after 5 cycles; (e) SEM image of fresh Si@TiN; (f) SEM image of Si@TiN after 5 cycles; (g) Top-view SEM image of fresh Si@TiN; (h) Top-view SEM image of Si@C after 5 cycles; (i) XPS data of Si@C after different cycles; (j) XPS data of Si@TiN after different cycles; (k) Relative percentage of different components for Si@C; (l) Relative percentage of different components for Si@TiN"

Fig. 8

The shortage of TiN layer. (a) The cycling performance of Si@TiN; the TEM image of Si@TiN before (b) and after (c) cycles"

Fig. 9

Inhibition of side reaction by silicon carbide ceramic layer. (a) The application of SiC in nuclear reactor[22]; (b) The TEM image of Si@SiC@C; (c) The activation energy for the reactions"

Fig. 10

In-situ TEM results. (a) The model of in-situ TEM sample holder; (b) Digital photo of in-situ TEM sample holder; (c) In-situ results"

Fig. 11

The enhancement of SiC layer for cycling performance. (a)-(c) HAADF image and corresponding Li,F EELS Mapping after 20 cycles; (d) The rate performance of Si@SiC@C; (e) The cycling performance of Si@SiC@C at alarge current of 1 A/g"