Enhanced rate capability of lithium deficient spinel via controlling cooling rate

Abstract

Lithium-deficient and Lithium-excess spinels LixMn1.6Ni0.4O4 (x = 1.05, 0.9) were synthesized by co-precipitation method assisted by ethylene glycol-oxalic acid. Control of cooling rates was performed in order to improve the crystallographic order, the lattice parameters and avoid the impurity precipitation. The samples were characterized physically and electrochemically. The best electrochemical performances were obtained for lithium-deficient spinels cooled at intermediate rates (2.2 °C min−1). For this optimized material, the discharge capacity was 122 mA h g−1 at 0.5C rate, retaining >83% of capacity at 10C rate and having good cycle life with >93.5% of initial capacity after 100 cycles at 0.5C rate.