The state-of-art lithium-ion batteries(LIBs)have achieved great commercial success during the past decades.The intercalation mechanisms in graphite anode and lithium transition metal oxide enabled its long-term stabil...The state-of-art lithium-ion batteries(LIBs)have achieved great commercial success during the past decades.The intercalation mechanisms in graphite anode and lithium transition metal oxide enabled its long-term stability in organic electrolytes.The classic electrolyte formula of lithium hexafluorophosphate(Li PF6)in carbonate solvents provided a benign solid electrolyte interphase(SEI)on the electrode surface.Subsequent researches on materials and electrolytes have improved the electrochemical stability and energy density for LIBs.Nevertheless,their adoptions,especially in electric vehicles and power grid have been obstructed owing to the safety concerns and environmental impact.The flammable carbonate solvents are easy to trigger fire and cause cell failure.The common used LiPF6 is sensitive to moisture which increases much difficulty to eliminate trace water in practical application.展开更多
Lithium-selenium(Li-Se) battery is a promising system with high theoretical gravimetric and volumetric energy densities, while its long-term cyclability is hard to realize, especially when a practical Se cathode with ...Lithium-selenium(Li-Se) battery is a promising system with high theoretical gravimetric and volumetric energy densities, while its long-term cyclability is hard to realize, especially when a practical Se cathode with high Se content, high Se loading, and high density is employed. The main obstacles are the sluggish conversion kinetics of the dense Se cathodes and the continuous deterioration of the Li-metal anodes.Here, by introducing an acetonitrile(AN)-based electrolyte and replacing the Li electrode with a lithiated graphite, we successfully build a hybrid conversion-intercalation system using a high-content(80 wt%),decent-loading(3.0 mg cm^(-2)), and low-porosity(44%) Se cathode. The as-designed lithiated graphite||Se(LG||Se) cell demonstrated a high Se utilization(97.4%), a long cycle life(3000 cycles), and an ultrahigh average Coulombic efficiency(99.98%). The cell also works well under lean-electrolyte(2 l L mg^(-1)) condition and shows outstanding safety performance in the nail-penetrating test. The combination affords the competitive comprehensive performances, including high volumetric and gravimetric energy densities, long cycling life, and superb safety of the LG||Se cell. In addition, with a newly-designed threeelectrode pouch cell, the lithiation of the graphite anodes could be done with an in-situ lithiation process,indicating the high potential of the as-proposed LG||Se cell for the practical applications.展开更多
文摘The state-of-art lithium-ion batteries(LIBs)have achieved great commercial success during the past decades.The intercalation mechanisms in graphite anode and lithium transition metal oxide enabled its long-term stability in organic electrolytes.The classic electrolyte formula of lithium hexafluorophosphate(Li PF6)in carbonate solvents provided a benign solid electrolyte interphase(SEI)on the electrode surface.Subsequent researches on materials and electrolytes have improved the electrochemical stability and energy density for LIBs.Nevertheless,their adoptions,especially in electric vehicles and power grid have been obstructed owing to the safety concerns and environmental impact.The flammable carbonate solvents are easy to trigger fire and cause cell failure.The common used LiPF6 is sensitive to moisture which increases much difficulty to eliminate trace water in practical application.
基金supported by the National Natural Science Foundation of China under Grant No. 51802225the funding from the State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology (P2020-001)。
文摘Lithium-selenium(Li-Se) battery is a promising system with high theoretical gravimetric and volumetric energy densities, while its long-term cyclability is hard to realize, especially when a practical Se cathode with high Se content, high Se loading, and high density is employed. The main obstacles are the sluggish conversion kinetics of the dense Se cathodes and the continuous deterioration of the Li-metal anodes.Here, by introducing an acetonitrile(AN)-based electrolyte and replacing the Li electrode with a lithiated graphite, we successfully build a hybrid conversion-intercalation system using a high-content(80 wt%),decent-loading(3.0 mg cm^(-2)), and low-porosity(44%) Se cathode. The as-designed lithiated graphite||Se(LG||Se) cell demonstrated a high Se utilization(97.4%), a long cycle life(3000 cycles), and an ultrahigh average Coulombic efficiency(99.98%). The cell also works well under lean-electrolyte(2 l L mg^(-1)) condition and shows outstanding safety performance in the nail-penetrating test. The combination affords the competitive comprehensive performances, including high volumetric and gravimetric energy densities, long cycling life, and superb safety of the LG||Se cell. In addition, with a newly-designed threeelectrode pouch cell, the lithiation of the graphite anodes could be done with an in-situ lithiation process,indicating the high potential of the as-proposed LG||Se cell for the practical applications.
