Instantaneous Surface Li<sub>3</sub>PO<sub>4</sub> Coating and Al–Ti Doping and Their Effect on the Performance of LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4</sub> Cathode Materials
Valeriu Mereacre, Nicole Bohn, Pirmin Stüble, Lukas Pfaffmann, Joachim R. Binder
Abstract
Using hydrogen peroxide (H2O2), a novel approach was applied for the synthesis of LiNi0.5Mn1.5O4 (LNMO) coated with Li3PO4 and doped with Al3+ and Ti4+ ions. The reaction between LNMO and H2O2 resulted in particles with a partially damaged surface. If the same reaction is done in the presence of lithium, aluminum, titanium, and phosphate ingredients, then all particle facets are intact and show no sign of destruction. It appears that the H2O2 decomposition activates the LNMO surface, generating perfect conditions for the homogeneous deposition of the Li, Al, Ti, and phosphate ions. Electrochemical investigations show a very slow fading process during the cycling, and even after more than 500 cycles, the obtained cathode material shows a high specific capacity of 127 mAh g–1 (at 1 C) (∼98% capacity retention) and an excellent Coulombic efficiency (99.5%).