Effect of Pore Size and Pore Wall Thickness of Mesoporous Phase in Tin Phosphate Composite on Electrochemical Cycling

We synthesized mesoporous∕crystalline composite with a mass ratio of 1:2 (mesoporous: crystalline), and the resulting mesoporous tin phosphate has different pore size depending on the alkyl chain length ( , 13, 15, and 17) of the surfactant . Because the crystalline phase to mesoporous phase mass ratio is fixed, a decrease in the capacity retention is mainly attributed to the deterioration of the mesophase. The mesoporous phase with smaller pore size causes higher capacity retention, with showing the highest capacity retention corresponding to 82%. This decreased to 67, 63, and 59% with increasing pore size, , 15, and 17, respectively.