Nanostructured nickel fluoride thin film as a new Li storage material

Nanostructured nickel fluoride thin films have been successfully prepared by pulsed laser deposition (PLD) and they showed significant electrochemical activity with lithium. The electrochemical performance of NiF2 thin film electrode was examined by the cyclic voltammetry and the discharge and charge measurements. A reversible capacity around 540 mAh/g was found after initial discharge. The electrochemical reaction process was revealed by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Li2NiF4 was identified as an intermediary product in the reversible electrochemical reaction of NiF2 with Li.

Graphical abstractNanostructured nickel fluoride thin films have been successfully prepared by pulsed laser deposition and the initial discharge and charge curves of NiF2/Li cells cycled between 0.01 V and 3.5 V at a constant current density of 10 μA/cm2 exhibit their electrochemical activity. The first discharge capacity of 650 mAh/g for the cell is found for the decomposition of NiF2. This corresponds to about 2.35 Li per NiF2. The capacity fading is only 0.4% per cycle after 40 charge–discharge cycles, indicating highly active thin film with high specific capacities and good cyclic performance. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) measurements suggest that multi-step reactions have been involved in the decomposition and composition of NiF2 and Li2NiF4 was identified as an intermediary product in the reversible electrochemical reaction of NiF2 with Li.Figure optionsDownload full-size imageDownload as PowerPoint slide