Pengaruh Penambahan Graphene Terhadap Cycle Life Baterai Lead Acid

Baterai pada kendaraan HEV beroperasi dalam kondisi partial state of charge. Kondisi partial state of charge mempercepat degradasi plat yang disebabkan oleh sulfasi pada plat. Sulfasi membentuk kristal PbSO4 irreversible yang bersifat non konduktif sehingga mengurangi cycle life baterai. Untuk meningkatkan cycle life dalam baterai lead acid maka dilakukan penambahan graphene. Graphene dicampur dengan lead oxide dalam larutan H2SO4 untuk membentuk active material. Active material kemudian melalui proses curing, soaking dan forming untuk membuat plat negatif. Sel baterai lead acid diuji SEM, XRD, cyclic voltammetry serta EIS. Kemudian sel baterai lead acid diuji cycle lifenya dalam kondisi partial state of charge. Setelah baterai mencapai cut off potential pada 1,7 volt baterai kembali diuji SEM, XRD, cyclic voltammetry serta EIS. Pada pengujian PSOC peningkatan umur siklus sebesar 12,35% setelah diberikan aditif graphene. Peningkatan ini jauh lebih kecil dari yang diharapkan. Dalam uji EIS terlihat peningkatan resistivitas internal plat dengan penambahan graphene antara sebelum dan sesudah PSOC adalah 869,8mΩ lebih kecil dibandingkan tanpa penambahan graphene sebesar 1530 mΩ. Peningkatan terjadi karena konduktivitas graphene yang lebih tinggi, Namun dari uji CV plat negatif dengan penambahan graphene memiliki reversibilitas lebih rendah dibandingkan tanpa penambahan graphene. Hal ini disebabkan pasting dan curing negative active material dibuat pada batch yang berbeda. Rendahnya reversibilitas menyebabkan rendahnya peningkatan umur siklus =================================================================================================== Battery in HEV vehicle operates in partial state of charge condition. Partial state of charge condition degrades battery plates in faster rate because of sulfation. Sulfation creates non-conductive irreversible PbSO4 crystal that decrease battery cycle life. Graphene would be added in this research to increase the cycle life of lead acid batteries Graphene mixed with lead oxide in H2SO4(aq) to create active material. Synthesized active material go through curing, soaking and forming process to make negative active material. Lead acid batteries tested with SEM, XRD, cyclic voltammetry, and electrochemical impendance specstrocopy method. Those testing followed with cycle life test in partial state of charge condition. After cut off potential reached, battery tested with SEM, XRD, cyclic voltammetry, and EIS method again. PSOC cycle life testing results shows graphene addition in negative plate increased cycle life 12,35%. This increase is lower than expected. EIS testing results shows that increase in internal resistance of plate is lower in plate with graphene 869,8 mΩ, than without graphene 1530 mΩ. Those increase caused by higher conductivity of graphene. However cv test results shows that graphene addition made plate reversibility lower. Those results caused by active material that was pasted and cured in different batch and poorly controlled condition. Lower reversibility caused lower cycle life increase