Metal/nanocarbon layer current collectors enhanced energy efficiency in lithium-sulfur batteries  

作　　者：Jia-Qi Huang Pei-Yan Zhai Hong-Jie Peng Wan-Cheng Zhu Qiang Zhang 

机构地区：[1]Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University [2]Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology [3]Department of Chemical Engineering, Qufu Normal University

出　　处：《Science Bulletin》2017年第18期1267-1274,共8页科学通报（英文版）

基　　金：supported by National Key Research and Development Program of China (2016YFA0202500, 2015CB932500);the National Natural Science Foundation of China (21776019, 21422604)

摘　　要：Lithium-sulfur （Li-S） batteries with intrinsic merits in high theoretical energy density are the most promising candidate as the next-generation power sources. The strategy to achieve a high utilization of active materials with high energy efficiency is strongly requested for practical applications with less energy loss during repeated cycling. In this contribution, a metal/nanocarbon layer current collector is proposed to enhance the redox reactions of polysulfides in a working Li-S cell. Such a concept is demon- strated by coating graphene-carbon nanotube hybrids （GNHs） on routine aluminum （AI） foil current collectors. The interracial conductivity and adhesion between the current collector and active material are significantly enhanced. Such novel cell configuration with metal/nanocarbon layer current collectors affords abundant Li ions for rapid redox reactions with small overpotential. Consequently, the Li-S cells with nanostructured current collectors exhibit an initial discharge capacity of 1,113 mAh g-1 at 0.5 C, which is -300 mAh g-1 higher than those without a GNH coating layer. The capacity retention is 73% for cells with GNH after 300 cycles. A reduced voltage hysteresis and a high energy efficiency of ca. 90% are therefore achieved. Moreover, the AI/GNH layer current collectors are easily implanted into current cell assembly process for energy storage devices based on complex multi-electron redox reactions （e.g., Li-S batteries, Li-O2 batteries, fuel cells, and flow batteries）.Lithium-sulfur(Li-S)batteries with intrinsic merits in high theoretical energy density are the most promising candidate as the next-generation power sources.The strategy to achieve a high utilization of active materials with high energy efficiency is strongly requested for practical applications with less energy loss during repeated cycling.In this contribution,a metal/nanocarbon layer current collector is proposed to enhance the redox reactions of polysulfides in a working Li-S cell.Such a concept is demonstrated by coating g^(-1)raphene–carbon nanotube hybrids(GNHs)on routine aluminum(Al)foil current collectors.The interfacial conductivity and adhesion between the current collector and active material are significantly enhanced.Such novel cell configuration with metal/nanocarbon layer current collectors affords abundant Li ions for rapid redox reactions with small overpotential.Consequently,the Li-S cells with nanostructured current collectors exhibit an initial discharge capacity of 1,113 m Ah g^(-1)à1at 0.5 C,which is$300 m Ah g^(-1)à1higher than those without a GNH coating layer.The capacity retention is 73%for cells with GNH after 300 cycles.A reduced voltage hysteresis and a high energy efficiency of ca.90%are therefore achieved.Moreover,the Al/GNH layer current collectors are easily implanted into current cell assembly process for energy storage devices based on complex multi-electron redox reactions(e.g.,Li-S batteries,Li-O_2batteries,fuel cells,and flow batteries).

关 键 词：Lithium-sulfur battery Nanostructured current collectors Polysulfides Energy efficiency Pouch cell 

分 类 号：TM912[电气工程—电力电子与电力传动]