Fe and V substituted Li2MnSiO4/C As Potential Cathode Material for Li-Ion Batteries

Abstract

Lithium transition-metal silicate materials are promising candidates for next generation Li-ion batteries since they allow Li extraction/insertion beyond one Li ion per formula unit. They consist of cheap, non-toxic and abundant elements. Here we focus on the synthesis and electrochemical performance of Fe and V substituted Li2MnSiO4. Cations were substituted to overcome poor stability of the undoped compound and increase conductivity, thus expected to increase the electrochemical performance. Up to 20 mole % Fe and 5 mole % V were incorporated into orthorhombic Pmn21 Li2MnSiO4 while keeping a high phase purity and the desired porous nano-sized structure. For materials with 20 mole % Fe substitution, the reversible Li intercalation capacity during slow cycling (C/33) was increased from 0.63 Li per formula unit for the undoped to 0.81 for the doped sample. A 5 mole % V substitution increased the reversible Li capacity from 0.65 Li per formula unit to 0.73.