The　positive　plates　with　conductive　materials,　Pb3O4　and　BaPbO3,　in　automotive　lead-acid　batteries　were　investigated　by　measuring　their　current　and　potential　distributions　in　the　course　of　formation　and　discharge.　It　is　found　that　these　two　conductive　materials,　especially　Pb3O4,　enhance　the　formation　in　the　initial　stage　greatly　and　that　they　make　the　current　and　potential　distributions　more　uniform.　In　the　discharge,　the　addition　of　Pb3O4　increases　the　capacity　of　the　positive　plate,　but　it　is　unfavorable　to　the　paste　curing　and　causes　poor　contact　between　active　mass　(AM)　particles　so　that　the　polarization　increases　greatly　at　3　C　discharge　rate.　The　BaPbO3　additive　improves　not　only　the　formation　but　also　the　discharge　performance　because　of　its　stability　in　acidic　media　and　at　high　polarization.　The　violent　charge　at　high　polarization　around　the　plates　in　the　initial　formation　can　lead　to　poor　AM　contact　and　high　polarization　resistance.　©　2008　Elsevier　B.V.　All　rights　reserved.