An innovative multi-layer pulsed laser deposition approach for LiMn2O4 thin film cathodes

Abstract

LiMn2O4 thin films were deposited via a pulsed laser deposition (PLD). For the first time a multi-layer PLD approach was applied to compensate for the lithium loss, with superior properties such as high stoichiometric flexibility and facile handling compared to conventional approaches. We highlight the influence of the main deposition parameters; fluency and oxygen background pressure on the oxidation state of Mn within the Li-Mn-O system, as well as its stoichiometry and hence its crystallographic phase. Furthermore we show that LMO films maintain characteristic twin peak electrochemical signature even at elevated sweep rates in combination with meagre polarization. These are encouraging results proving that multi-layer PLD is a facile and convenient approach to overcome the intrinsic drawback of lithium deficiency, assuring deposition of Li containing thin films electrodes with high electrochemical activity.