Destruction behavior of carbon hybridized Li2MnSiO4 and Li2FeSiO4 nanoparticles for cathode materials

Abstract Carbon-hybridized Li 2 MSiO4 (M=Mn, Fe) nanoparticles were synthesized using the spray pyrolysis method subsequent to grinding and heat treatment. The carbon-hybridized Li 2 MnSiO 4 particles exhibited excellent cycle performance up to 1.21 Li/formula-unit delithiation(charged)/lithiation(discharged) cycles. However, the discharge capacity decreased rapidly under high delithiation/lithiation conditions of more than 1.25 Li/formula-unit, although Li 2 FeSiO 4 has better cycle stability under delithiation/lithiation of 1.5 Li/formula-unit. The local structure differences examined using XANES between Li 2 MnSiO 4 and Li 2 FeSiO 4 revealed that the coordination polyhedral for Mn ion changed from tetrahedron to octahedron by cycling, while that of Fe ion was maintained as a tetrahedron. Results suggest that the coordination preference of Mn ion in the structure governs the cycle performance.