Lthium metal protection intralayers

CECILIA ANDREA CALDERÓN; DANIEL BARRACO; JERNEJ BOBNAR; MANUEL OTERO; BOSTJAN GENORIO; ALEN VIZINTIN; EZEQUIEL P. M. LEIVA; ROBERT DOMINKO

Bologna

Congreso; 69th annual meeting of the international society of electrochemistry; 2018

Metallic lithium is considered as anode material in next generations of different types of batteries since it offers high energy density and in the combination with high-voltage or high-capacity cathodes cells much higher energy density (gravimetric and volumetric) can be obtained. But due to its thermodynamic instability with aprotic solvents and salts used as electrolytes, its practical use in the commercial cells is limited. In the contact with electrolyte, metallic lithium forms unstable solid electrolyte interface whichresults formation of dendrites and constant lithium and electrolyte consumption during electrochemical cycling. That can be stopped or at least reduced by proper interlayer which has to be ionically conductive and electronically insulating, so it can act as an artificial interlayer. In this contribution we present and compare three strategies of lithium metal protection. A fluorinatedreduced graphene oxide interlayer (FGI) deposited on the top of metallic lithium effectively suppresses formation of high surface area lithium (HSAL), but due to formation of cracks during stripping and deposition process part of the surface of lithium is exposed to electrolyte. Polymer ionic liquids offer more plastic behavior compered to FGI, but this approach is less resistive for dendrites growth through the membrane deposited on lithium surface. Finally, the third option studied in our lab is deposition of metal fluorides on the lithium surface. Advantages and problems of all three approaches will be discussedbased on stripping and deposition tests in the symmetrical cells, microscopy, impedance spectroscopy and electrochemical behavior in the full cell (containing sulfur or LFP cathodes).