The　effects　of　several　rare　earth　oxides　and　fluorine-containing　compounds　as　additives　on　the　hydrogen　evolution　at　the　negative　plates　containing　commercial　and　purified　carbon　materials　in　valve-regulated　lead-acid　(VRLA)　batteries　have　been　studied　by　means　of　the　constant　current　polarization　and　hydrogen　gassing　measurements.　The　activated　carbon　(AC)　and　iron　impurity　in　the　carbon　materials　greatly　accelerate　the　hydrogen　evolution.　La2O3,　Sm2O3,　Gd2O3,　Nd2O3,　Dy2O3　and　polytetrafluoroethlene　(PTFE)　as　electrolyte　additives　inhibit　the　hydrogen　evolution.　When　the　hydrogen　evolution　polarization　potential　is　small　as　in　the　case　of　the　oxygen　depolarization　in　the　oxygen　cycles,　the　addition　of　0.025%　PTFE　and　0.025%　Dy2O3　additives　to　electrolyte　increase　its　overpotential,　but　these　two　additives　can　promote　the　hydrogen　evolution　at　negative　plates　containing　activated　carbon　(AC),　expanded　graphite　(EG)　or　flake　graphite　(FG)　with　low　impurity　contents.　In　the　test　of　cycle　life　of　the　12　V　12　Ah　VRLA　batteries　with　the　negative　plate　containing　acetylene　black　(AB),　the　combined　additive　of　PTFE　and　Dy2O3　greatly　increases　the　charge　efficiency　and　thus　decreases　water　loss.