Plasma enhanced atomic layer deposition of a (nitrogen doped) Ti phosphate coating for improved energy storage in Li-ion batteries

The use of Ti phosphate as a functional coating for Li ion battery electrodes has been investigated, well the effect nitrogen doping on its electrochemical properties. First, previous knowledge PE-ALD (using an exposure sequence trimethylphosphate plasma–oxygen plasma–titaniumisopropoxide) was used to study altered process using plasma, i.e. TMP* - N2* TTIP. This enabled deposition doped (6 at.%) with growth per cycle 0.4 nm/cycle. Next, dual-source precursor (diethylphosphoramidate or DEPA*) introduced instead TMP*, allowing higher rate (0.6 nm/cycle) and level (8.6 at.%). ionic transparency slightly decreased due incorporation, but effective transversal electronic conductivity showed be three times after doping. A 2 nm (un)doped significantly improved capability lithium nickel manganese cobalt oxide (NMC) electrode, increasing amount energy that can stored at high (dis)charging speeds factor 10 (at 5C). In addition, undoped titanium offered increased stability, retaining 84% capacity 100 cycles 1C respect 79% uncoated electrode.