Boron activity in the inactive Li2MnO3 cathode material

Abstract

Boron substituted Li2MnO3 cathode materials have frequently been studied and found to be inactive. In this reseach, crystal and electronic properties of the Li-ion cathode material with boron substitution having general formula; “Li2Mn1-xBxO3” (where x has values of 0.00, 0.05, 0.10, 0.15 and 0.20, respectively) were studied. The study revealed that, with the substitution of boron atoms in the manganese coordinates in the Li2MnO3 cathode materials, boron atoms acted as a landmark for the parent oxides by forming LiBO2 crystal domains. In the studied samples, boron atoms were determined as the key to construct new crystals and to restrict the excess of oxygen in the materials. Beyond the boron coordinations, the manganese atoms formed a cubic LiMn2O4 crystal structure which was reported to have good electrochemical properties. With the formation of the LiMn2O4 crystal, the substituted samples became a polycrystalline material with Li2MnO3- LiBO2- LiMn2O4 crystals. The obtained structure in the cathode materials have similarity with the general formula xLi2MnO3·(1-x)LiMn2O4 which had been reported to have good intercalation and electrochemical properties.