Separator-free and concentrated LiNO 3 electrolyte cells enable uniform lithium electrodeposition

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 8; no. 7; pp. 3999 - 4006
• Main Authors: Rodriguez, Rodrigo, Edison, Ruth A., Stephens, Ryan M., Sun, Ho-Hyun, Heller, Adam, Mullins, C. Buddie
• Format: Journal Article
• Language: English
• Published: 18.02.2020
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C9TA10929C

Imaging of lithium electrodepositions revealed that in the absence of a compressed porous separator, achieved via a plastic washer, dendrite-free lithium was deposited from glyme solutions of 1 M LiNO 3 . When the 1 M LiNO 3 in glyme was coupled with a 1 M LiFSI salt, high coulombic efficiencies were also attainable in both Li|Cu and anode-free LFP|Cu cells. However, dendrite resurgence was observed in cycled lithium coin cell electrodes when a porous separator was utilized. This was attributed to the restriction of Li + flux to the electrode surface induced by the porous and tortuous structure of the polymer separator. At these pores, localized current densities, which exceeded the applied current density, and a non-uniform Li + flux resulted in dendritic lithium growth. Replacement of the separator by a washer normalized the current distribution and provided for non-dendritic lithium deposits in coin cells.