Synthesis of LiNi0.5 Mn1.5 O4 cathode materials with different additives: Effects on structural, morphological and electrochemical properties

In this work, LiNi0.5 Mn1.5 O4 spinel type materials have been prepared by spray drying an aqueous solution of acetates and subsequent calcination of the dried precursors. Three different additives, namely polyvinylpyrrolidon (PVP), citric acid and urea have been used and their influences on the structure, morphology and electrochemical performance of the final cathode materials have been examined. Results show that the employed additives increase the purity of the disordered spinel phase and thus lead to higher discharge capacities. By the use of PVP and citric acid, a more stable cycling behavior and a better rate capability are achieved due to the well-controlled secondary particle morphology. Regarding the microstructural changes, flake-like secondary particle morphology has been observed for the use of PVP in the synthesis process, as in former work reported [J. Power Sources, 293, 137 (2015)]. The evolution of this structure is examined in more detail and possible way of formation is proposed.