Understanding the Sn Loading Impact on the Performance of Mesoporous Carbon/Sn‐Based Nanocomposites in Li‐Ion Batteries

Abstract Herein, we report a systematic study to understand the influence of the amount of tin metal precursor salt on the formation of carbon/tin hybrid materials and their performances as anodes in Li‐ion batteries. Small Sn metallic particles (ca. 5 nm) covered by a SnO 2 layer were uniformly dispersed in a mesoporous carbon for a low loading of tin; whereas, for higher Sn loadings, the formation of Sn‐based particles aggregates (ca. 200 nm) is promoted as well. By increasing the Sn loading from 20 to 80 %, the irreversible capacity was successfully reduced and the reversible capacity improved. This could be related to the decrease of the C/Sn hybrids specific surface area and the increase of the Sn active species. For long‐term cycling, capacity fading was observed, particularly for high Sn loadings assigned to the Sn nanoparticles placed outside the carbon network, which upon lithiation witness large volume expansion, leading to severe particle growth and agglomeration. Therefore, similar reversible capacities at long cycling are reached, no matter the Sn loading. For optimal electrochemical performances, it appears that a balance between the amount of Sn and uniform small Sn‐based particles dispersion within carbon matrix must be assured to design high‐performance anodes for Li‐ion batteries.