Double-shelled support and confined void strategy to improve the lithium storage properties of SnO₂/C anode materials for lithium-ion batteries

Abstract

As promising anode materials for lithium-ion batteries, SnO 2 materials have triggered significant research efforts due to their high theoretical capacity. However, their practical applications are impeded by poor cycle life caused by structural pulverization and large volume changes during cycling. Thus, development of strategies for improving the cycling performance of SnO 2 anodes is indispensable. Herein, a peculiarly nanostructural SnO 2 /C composite (denoted as SnO 2 @DSC) with double-shelled carbon support and confined void is fabricated, in which SnO 2 is quasi confined in the void-space between two shells. It is suggested that the as-prepared SnO 2 @DSC has two unique advantages: On the one hand, SnO 2 is quasi encapsulated into the confined void between two shells, the huge volume change is largely buffered and its electrical connectivity is guaranteed, because even if the SnO 2 detach from the outer shell, it can be immobilized again at interior shell; On the other hand, the structure integrity of electrode could be guaranteed by virtue of the dual-support of mechanically flexible double-shelled hollow carbon nanospheres. As a result, the as-prepared SnO 2 @DSC exhibited an excellent cycling performance, delivering a high reversible capacity of 838.2 mAh g -1 at 200 mA g -1 even after 500 cycles.The composition of SnO 2 @DSC was closely studied by elemental identification, XPS and Raman characterizations, as gave in Figure 3. Figure 3(a-d) display the EDX elemental mappings for carbon, oxygen, and tin based on the area of the SEM image (Figure 3a), respectively, which well match the observation in the SEM image, implying carbon, oxygen, and tin are well distributed throughout the SnO 2 @DSC composite. Figure 3e shows the typical high-resolution XPS spectra of Sn 3d, in which two peaks respectively centered at 487.5 and 495.8 eV are observed and corresponding to binding energies of Sn 3d 5/2 and Sn 3d 3/2 , respectively. The binding energy of Sn

Origin of Capacity Increasing in a Long‐Life Ternary Sn–Fe3O4@Graphite Anode for Li‐Ion Batteries

“…However, it has been observed that the specific capacity of electrode increased gradually with cycling. And this phenomenon was reported in previous publications on Sn‐based or Fe 3 O 4 anodes, and also in almost the transition metal oxide‐based anode materials. In some reports, this additional reversible capacity was even beyond the theoretical capacity calculated based on their reaction mechanism …”

Tailored Yolk–Shell Sn@C Nanoboxes for High‐Performance Lithium Storage

“…The capacity decreased initially and increased gradually after 30 cycles. This phenomenon has been commonly observed in Sn‐based anodes, which is associated with the reversible formation of a polymeric gel‐like layer via electrolyte decomposition and the activation of Sn particles due to improved accessibility of lithium ions upon deep cycling . Notably, the capacity maintained as high as 810 mA h g −1 even after 500 cycles, which was 90% of the capacity of the second cycle, suggesting an exceptional cycling stability of the Sn@C‐2.…”

Natural Porous Biomass Carbons Derived from Loofah Sponge for Construction of SnO2@C Composite: A Smart Strategy to Fabricate Sustainable Anodes for Li–Ion Batteries

“…In addition, two typical peaks are measured to prove the existence of carbon. The broad peaks at 1340 and 1590 cm −1 are assigned to the D (disordered carbon) and G (graphitic carbon) peaks, respectively . The D band comes from the disordered carbon by sp 3 defects, and the G band corresponds to the sp 2 carbon‐bonded graphitic structure ,.…”