Investigation on Li2FeSiO4 and Li2FeSiO4/C synthesised through facile solid-state reaction

In the pursuit of high energy batteries, Li2FeSiO4 cathode with ultrahigh theoretical capacity has drawn great attention. However, engineering the Li2FeSiO4 cathode to achieve satisfactory electrochemical performances are severely impeded by stubborn impurities, low intrinsic conductivities and complex synthesis procedure. In this work, facile solid-state reaction is investigated to synthesise high purity Li2FeSiO4 and Li2FeSiO4/C cathode. It is found that the choice of precursors plays a crucial role in suppressing the formation of impurities. The accessible capacity of high purity Li2FeSiO4 product is still constrained by poor conductivities; in contrast, the impurity-free Li2FeSiO4/C composite exhibit greatly improved electrochemical performances.