(444f) 3D Printed Nanoporous Separators for High Cycling Stability Li-Ion Batteries

Separators with controllable microstructures are a crucial component of high-power high-energy Li-ion batteries. Microstructural inhomogeneities within the separator have been linked to battery failure by localized current hot spots. Here, we demonstrate the synergetic effect of using projection micro-stereolithography and polymerization induced phase separation to fabricate hexanediol diacrylate (HDDA) separators with controlled multi-length-scale morphologies and high porosities (26.6% - 63.1%). Systematic variation of the microstructure of the HDDA separators enabled the examination of structure-property relationships with respect to battery stability and performance. The graphite/NMC 622 cell assembly with the HDDA separator showed better high-rate capability and capacity retention than the Celgard 2325 separator, delivering a reversible capacity of 143 mAh/g with a 99.85% capacity retention after 100 cycles at 1C.