Journal of the Electrochemical Society, Vol.147, No.12, 4411-4420, 2000
Chemical synthesis of tin oxide-based materials for Li-ion battery anodes - Influence of process parameters on the electrochemical behavior
Novel chemical approaches were developed to synthesize SnO2-based powders. Overall, chemically derived Sn oxide based-materials heat-treated in air show an improved cyclability compared to commercially derived SnO2. However the cyclability of SnO2:B2O3:P2O5 = 1:0-25:0.25 is remarkably affected by the generation of gels or precipitates. Homogeneous gels reveal better cyclability and less aggregation of Sn clusters in comparison to precipitated oxides. Air-treated precursors of SnO2:Li2O:B2O3:SiO2 = 1:0.39:0.13:0.48. regardless of the process, exhibit a larger capacity fade than amorphous compositions of SnO2:B2O3:P2O5 = 1:0.25:0.25. This is due to a breakdown of the initial homogeneous state of the components in the as-prepared precursor and the segregation of crystalline SnO2, despite a higher ratio of spectator atom:Sn. Finally, in situ reduction of chemically synthesized precursors leads to a decrease in the first-cycle loss, albeit exhibiting more fade due to large grained tin. Thus by selecting a suitable chemical process and the spectator species, it is possible to synthesize compositions that represent a homogeneous distribution of tin oxide, while controlling the aggregation of Sn clusters during cycling. This judicious control of the process and the homogeneity of the tin oxide compositions can lead to improved cyclability and minimization of capacity fade.