Commercial-grade　fumed　silica　was　dispersed　by　mechanical　shearing　and/or　ultrasonic　force　to　produce　dispersed　silica　particles　with　different　sizes.　The　light-scattering　technique　and　a　diagrammatic　method　of　extrapolation　used　to　eliminate　the　influence　of　particle　interaction　were　applied　to　determine　the　size　of　the　particles.　Then,　the　effect　of　particle　size　on　the　gelation　of　fumed　silica　in　sulphuric　acid　medium,　as　well　as　some　electrochemical　properties,　such　as　ion　transfer　and　redox　capacities　of　lead,　in　the　gelled　electrolyte　were　examined.　The　results　showed　that　the　size　of　dispersed　particles　affected　the　gelation　of　fumed　silica　itself:　with　increasing　size,　the　thixotropy　of　the　system　increased　and　the　gelling　time　decreased,　particularly　for　those　particles　obtained　only　by　simple　stirring.　The　strength　of　the　gel　increased　with　increasing　particle　size.　At　an　identical　silica　content,　the　increase　in　particle　size　led　to　a　decrease　in　the　density　of　the　particles:　this　weakened　the　three-dimensional　structure　of　the　silica　particle　network　and　reduced　the　efficiency　of　ion　transfer.　However,　the　effect　of　silica　particle　size　on　the　redox　capacities　of　lead　was　negligible.