Improving the structure stability and electrochemical performance of Li2MnSiO4/C cathode materials by Ti-doping and porous microstructure

Li 2 MnSiO 4 cathode material suffers from structure collapse and thus rapid capacity fading during cycling. Here, we employed the stable [TiO 6 ] ligands as a local pillaring framework to improve the structural stability. Porous Li 2 MnSi 1- x Ti x O 4 /C nanoparticles were successfully synthesized by employing SBA-15 as Si source. Rietveld refinement revealed Ti substitution caused the phase composition transition (partial Pmnb to Pmn 2 1 phase), which contributed to higher charge/discharge capacity. XPS confirmed the positions of Ti 4+ and the formation of [TiO 6 ] octahedrons. 15 mol% Ti doped sample (S-LMST) showed a highest specific surface area of 114.25 m 2  g −1 and delivered a highest initial discharge capacity of 182.7 mAh g −1 under 1.5–4.8 V. Interestingly, S-LMST electrode presented excellent cycling stability, especially retaining ∼94% of initial discharge capacity after 8th cycles, while pristine Li 2 MnSiO 4 only retained ∼55%. Additionally, S-LMST electrode exhibited higher discharge capacity under lower cut-off voltage. The maximal initial discharge capacity can reach to 259.7 mAh g −1 in 1.5–4.6 V. The enhanced cycling stability can be mainly ascribed to the pillaring effect of [TiO 6 ] octahedrons and the decreased charge transfer resistance, as well as the improved Li + diffusion coefficient due to porous structure.