Gelatine based gel polymer electrolyte towards more sustainable Lithium-Oxygen batteries

Abstract

The lithium-oxygen battery has attracted wide interest thanks to its very high theoretical energy density, and as such it is considered by many as a valid battery of the future candidate. However, the challenges in its practical application are many, such as liquid electrolyte evaporation in semi-open systems, as well as solvents instability in a highly oxidizing environment. In this work, we propose to use gelatin, from cold water fish skin, a waste from the fishing industry, to prepare an efficient gel electrolyte for future Li-O2 battery applications. After a single step methacrylation in water, methacrylated gelatine is directly cross-linked in presence of liquid electrolyte through UV- initiated radical polymerization. The obtained gel polymer electrolytes present good thermal and mechanical properties, good electrochemical stability against Li metal and ionic conductivities as high as 2.51 mS cm−1 at room temperature. the Li-O2 cells assembled with this bio-renewable gel polymer electrolytes were able to perform more than 100 cycles at 0.1 mA cm−2, under constant O2 flow, at room temperature and at a fixed capacity of 0.2 mAh cm−2. Cathodes post- mortem analysis confirmed that the cross-linked gelatin matrix was able to slow down solvent degradation and therefore enhance the cell reversibility.