Wednesday, 4 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
Efforts to realize lithium metal as anode limited by dendrite formation and low Coulombic efficiency. These challenges stem from extensive reaction of lithium with electrolyte, deposition of more dead lithium and formation of unstable solid electrolyte interface. Herein, we revealed a homogeneous lithium deposition and dendrite suppression via regulating lithium flux with polyethylene oxide (PEO) film coated copper electrode in 1M LiTFSI, DME/DOL (v/v 1/1) and 2 wt% LiNO3 electrolyte. PEO coating reinforces a thin and robust SEI layer film formation by hosting lithium and regulating the inevitable reaction of lithium with electrolyte. The modified electrode showed a stable and an extremely excellent Coulombic efficiency over 200 cycles with low voltage hysteresis (~30 mV) at rate of 1 C. In comparison the modified electrode tested with 1M LiPF6, EC/DEC (v/v 1/1) electrolyte and showed a rapid capacity fading due to PEO film damage with fluoride ion interaction. This enhanced cycle life and capacity retention results from the synergy of PEO coating, high electrode-electrolyte interface compatibility, stable polar oligomer formation from reduction of 1, 3-dioxolane and generation of SEI stabilizing nitrite and nitride upon lithium nitrate reduction in an ether electrolyte.