Vertical graphene growth on uniformly dispersed sub-nanoscale SiO_x/N-doped carbon composite microspheres with a 3D conductive network and an ultra-low volume deformation for fast and stable lithium-ion storage

Abstract

Vertical graphene growth on subnanoscopically and homogeneously dispersed SiOx and carbon composite microspheres shows fast and stable lithium ion storage behavior.

Nanoscopically and uniformly distributed SnO2@TiO2/C composite with highly mesoporous structure and bichemical bonds for enhanced lithium ion storage performances

“…cyclability and rate performance. 42,43 Additionally, the formation of Ti-O-C and Sn-O-C bonds in the interfaces can promote interfacial charge transfer and enhance the structural stability of SnO 2 @TiO 2 /C, thus contributing to fast lithium ion transport and long cycling life. 15 Furthermore, the phase boundaries and mesoporous structure can afford the storage of additional Li + and thus achieve a high capacity.…”

“…15 Furthermore, the phase boundaries and mesoporous structure can afford the storage of additional Li + and thus achieve a high capacity. 42,43 Finally, the ultrasmall nanocrystals can supply enormous active storage sites and shorten the Li + diffusion distance, thus facilitating high capacity and enhancing the rate capability. 42,43…”

Ge nanocrystals tightly and uniformly distributed in a carbon matrix through nitrogen and oxygen bridging bonds for fast-charging high-energy-density lithium-ion batteries

“…13,17 High Intensity ratio (1.13) of D and G peaks suggests that the carbon contains plentiful defects beneficial for Li + storage. 8,10,13 Four elements of Ge (11.6 at%), C (73.2at%), N (9.1 at%), and O (6.1 at%) ( Ge-O, respectively, to imply the presence of elemental Ge, Ge-N-C, and Ge-O-C. 17,25 The C 1s spectrum ( Fig. 2e) reveals three peaks at 284.8, 286.1, and 287.2 eV attributed to C-C, C-N/C-O, and C=O, respectively, 13,17 to confirm the formation of N,O co-doped carbon.…”

“…The results show that the size of Ge nanoparticles increases and their structures change from crystalline to amorphous after cycling, which is consistent with the previous reports. 28,29 Therefore, the increase of electrode thickness is mainly caused by the increase of the size of Ge nanoparticles and 13 (iii) Nanoscopically and evenly distributed structure can make strain uniformly distribute in the nanocomposite to mitigate volume expansion; 7,8,10 (iv) Highly mesoporous structure has a accommodation capacity of volume expansion;…”

“…Commercial graphite anode due to low capacity 1 and poor rate performance 2 cannot meet the requirement of high-energy/power-density lithium-ion batteries (LIBs) for electric vehicles, which need longer driving mileage and shorter charge time. 3,4 Consequently, enormous anodes with higher capacity and better rate capability are fabricated in recent years, such as Si, 5 Ge, 6 Sn, 7 and their corresponding oxide, [8][9][10][11][12] and transition metal sulfide 13,14 etc. Among them, Ge has come to public concern due to high specific/volumetric capacity of 1624 mAh g -1 /8600 mAh cm -3 , 15,16 and high Li + diffusivity 6,17 to lead to an amazing rate capability up to 1000 C. 18 However, Ge experiences large volume change of ~230% on cycling to bring about electrode pulverization, and thus cause poor cyclablity.…”