To　suppress　sulfation　in　the　negative　electrode　of　the　lead　acid　battery　(LAB),　N-doped　carbon　(NC)　is　synthesized　by　annealing　chitosan　under　N-2　atmosphere.　As　an　additive,　NC　can　improve　LAB＇s　cycle　stability　through　the　suppression　of　irreversible　sulfation.　It　is　attributed　to　the　formation　of　a　carbon　conductive　network　in　the　negative　electrode,　which　can　improve　electronic　conductivity　and　control　growth　of　PbSO4　crystals.　Therefore,　the　LAB　with　Pb/NC　negative　electrode　delivers　a　long　cycle　life　of　1102　at　the　current　of　0.2　A.　It　is　about　3.6　times　that　of　LAB　with　Pb　electrode.　Potentially,　the　approach　of　preparing　NC　is　simple　and　inexpensive.　It　is　expected　to　be　commercialized.　(C)　2019　Elsevier　B.V.　All　rights　reserved.