Capillary contraction force is proportional to the surface tension of the liquid. In silica sol-type shells, the liquid in the capillary pores is mainly water. In ethyl silicate-type shells, the liquid in the capillary pores is a mixture of alcohol and water. The surface tension σ of the alcohol-water mixture is relatively low, resulting in a smaller contraction pressure P and larger capillary pore diameters in the gel. Therefore, larger capillary pore diameters give ethyl silicate-type shells better breathability compared to silica sol-type shells. Additionally, the capillary contraction force P in ethyl silicate-type shells is smaller, leading to relatively less volume contraction in the gel and shallower dense packing of particles. Thus, while the strength of ethyl silicate-type shells may not be as high as that of silica sol-type shells, they are less prone to fragmentation or cracking, resulting in higher yield rates.