Aluminum^-graphene battery is promising for its abundant raw materials,high power density,ultralong cycle life and superior safety.However,the development of aluminum^-graphene battery is currently restricted by its i...Aluminum^-graphene battery is promising for its abundant raw materials,high power density,ultralong cycle life and superior safety.However,the development of aluminum^-graphene battery is currently restricted by its insufficient cathode capacity,calling for a newly developed working mechanism.In addition,an irregular constant increase of the cathode capacity was always observed during cycling,but cannot be explained based on the current understanding.Here,we observed an increase of specific capacity by 60%with stable Coulombic efficiency of 98%during 7000 cycles life of Al-graphene batteries employing AlCl3/ET3NHCl electrolyte.We demonstrated this growing cathode capacity is attributed to an increasing contribution of capacitive charge storage during cycling,because a gradually enlarged surface area as capacitive active sites is enabled by the exfoliation of graphitic cathode during the periodic intercalation process.Moreover,the graphene cathode was exfoliated more significantly in AlCl3/ET3NHCl than 1-ethyl-3-methylimidazolium chloride-based electrolyte,which results from the heavier stress on the graphene layers caused by the larger intercalants in AlCl3/ET3NHCl.The common intercalation of cations with AlCl4-clusters was therefore supposed to occur during charging.This new proposed mechanism can offer the new thought for future design on high-capacity cathode of Al-ion battery.展开更多
基金supported by the National Natural Science Foundation of China(No.51533008)National Key R&D Program of China(No.2016YFA0200200)+1 种基金Key Research and Development Plan of Zhejiang Province(2018C01049)Fujian Provincial Science and Technology Major Projects(No.2018HZ0001-2)。
文摘Aluminum^-graphene battery is promising for its abundant raw materials,high power density,ultralong cycle life and superior safety.However,the development of aluminum^-graphene battery is currently restricted by its insufficient cathode capacity,calling for a newly developed working mechanism.In addition,an irregular constant increase of the cathode capacity was always observed during cycling,but cannot be explained based on the current understanding.Here,we observed an increase of specific capacity by 60%with stable Coulombic efficiency of 98%during 7000 cycles life of Al-graphene batteries employing AlCl3/ET3NHCl electrolyte.We demonstrated this growing cathode capacity is attributed to an increasing contribution of capacitive charge storage during cycling,because a gradually enlarged surface area as capacitive active sites is enabled by the exfoliation of graphitic cathode during the periodic intercalation process.Moreover,the graphene cathode was exfoliated more significantly in AlCl3/ET3NHCl than 1-ethyl-3-methylimidazolium chloride-based electrolyte,which results from the heavier stress on the graphene layers caused by the larger intercalants in AlCl3/ET3NHCl.The common intercalation of cations with AlCl4-clusters was therefore supposed to occur during charging.This new proposed mechanism can offer the new thought for future design on high-capacity cathode of Al-ion battery.
基金This work is supported by the National Natural Science Foundation of China(51533008,21325417,51603183,51703194,51803177 and 21805242)the National Key R&D Program of China(2016YFA0200200)+3 种基金Fujian Provincial Science and Technology Major Projects(2018HZ0001-2)Hundred Talents Program of Zhejiang University(188020*194231701/113)the Key Research and Development Plan of Zhejiang Province(2018C01049)the Fundamental Research Funds for the Central Universities(2017QNA4036 and 2017XZZX001-04).
