Evaluation of NP-MnFe2O4 as an Efficient Nanocatalyst for Air Cathode and 1-Octyl-3-methyl Imidazolium Hexafluorophosphate [Omim][PF6] as a Green Electrolyte in Rechargeable lithium-Air Battery

A simple, new and low-cost design of Li-air battery was introduced. An effective synthesized nanocatalyst for modifiying of air cathode, filter paper as a simple separator and a conductive ionic liquid namely 1-Octyl-3-methyl imidazolium hexafluorophosphate abbreviated [Omim][PF6] as a non-aqueous and green electrolyte in battery were used. The MnFe2O4 nanoparticles (NP-MnFe2O4) which consistingof transition metal-metal oxide components was synthesized in our labrature. High discharge capacity, non-flammability of electrolyte, high reversibility, long lifetime and low over potential were observed in electrochemical tests of the battery. Synthesized nanocatalyst was characterized using XRD, FTIR and SEM techniques. XRD results show that a nanocatalyst have a particle sizes of 16-28 nm that distributed on cathode uniformly and performance of battery was improved to more than 1000 cycles compared to battery without any catalyst. The discharge capacity at current density of 0.2 mA cm-2 and charge potential range of 2.0-4.2 V for battery with catalyst/green electrolyte and without catalyst/common organic electrolyte were 3391 and 1012 mAh g-1,respectively. Furthermore, the usage of an ionic liquid as electrolyte leads to the increase the safety and lifetime of battery. Because of used electrolyte have high boiling point amount (>350 Celcius), so if it released to the environment due to the destruction or life expires of battery, don’t seriously damage to the environment because it is not easily evaporated.