Synthesis and transport properties of nanostructured lithium manganese silicate (Li2MnSiO4) as Li-ion battery cathode material

Orthorhombic-Li2MnSiO4 (LMS) in almost pure phase is prepared by easy and fast urea combustion method by optimizing the metal Si and Li precursors for the first time. Morphological characterization reveals the formation of nano-sized particles with pores/voids which is further confirmed by N-2-adsorption analysis. The detailed transport properties of urea combustion derived LMS have been studied for the first time also. LMS is found to exhibit extraordinarily high conductivity i.e., 4(+/- 1) x 10(-8) S cm(-1) and authenticated well by different supplementary techniques. This superior transport behavior of urea combustion derived-LMS is attributed to its unique morphology, porosity and higher interfacial area/interphases or grain boundaries in nanocrystalline-LMS that probably act as short-circuiting pathways for facile and easy ionic movement and hence higher ionic conductivity is expected. Moreover, the nano-phase of LMS exhibits quite low activation energy than that of LMS reported in literature. This decrease in activation energy may also be attributed to extended interfacial area in nanocrystalline meso-porous LMS and further support the high conductivity of presently studied LMS. Improved electrochemical performance of pristine-LMS is also observed. Our preliminary results on electrochemical performance of porous-LMS emphasize that conductivity of LMS seems not to be a major reason of poor cyclability as stated in most of the literatures, but structural instability or amorphization of LMS probably due to Jahn-Teller distortion and manganese dissolution could be the main causes of poor electrochemical cyclability of LMS. (C) 2016 Elsevier B.V. All rights reserved.