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

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2017,（18）
• 页码范围: 1267-1274
• 页数: 8页
• 语种: 英文

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 demonstrated by coating graphene-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 mAh g-1 at 0.5 C,which is ～300 rnAh 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 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-O2 batteries,fuel cells,and flow batteries).