Formation, structure and electrochemical performance of nano-sized Li2FeSiO4/C synthesized with the co-incorporation of citric acid and glucose followed by a two-step annealing

Abstract

Nano-sized Li₂FeSiO₄/C composites are synthesized using a simple recipe via the co-incorporation of citric acid and glucose with various molar ratios followed by a two-step annealing. Citric acid and glucose traditionally recognized as reducing agents, size reduction agents and carbon sources are found to play different roles here in which glucose has a far more effective and critical role to play in size reduction and citric acid alleviates the agglomeration of nanoparticles more effectively than before. It is reported for the first time that the decrease in intensity ratio between the reflections around 2θ = 24.3° and 33.1° of monoclinic Li₂FeSiO₄ with space group of P2₁ with increased amounts of citric acid and glucose originates from the increased intermixing occupancies between Fe and Li. An appropriate intermixing occupancy between Fe and Li could facilitate the electrochemical performance of Li₂FeSiO₄. This study provides a new idea to optimize the electrochemical performance of Li₂FeSiO₄ by controlling the intermixing occupancy of Fe and Li through introducing some organic substances during synthesis.