One-pot synthesis of LiFePO4–carbon mesoporous composites for Li-ion batteries

Abstract

The synthesis of LiFePO4–carbon mesoporous composites by a one-pot soft-template approach is reported along with their performances as positive electrodes for Li-ion batteries. The synthesis is based on the multi-constituent co-assembly of triblock copolymer, resol and (Li, Fe, P) precursors followed by thermal treatment to in-situ generate the carbon matrix with embedded LiFePO4 particles. The effects of the Fe/Li precursor type and the thermal annealing temperature on the phase formation, mesostructural regularity, porosity and Fe oxidation state were systematically investigated by a large panel of analysis techniques. This new synthesis method allowed the successful synthesis of mesoporous LiFePO4–carbon composites with high surface area, defined pore size and small homogenously distributed LiFePO4 particles (20–50nm). These composites can be used as electrodes without extra carbon black additive and demonstrate high rate capability (up to 10C) with a significant capacity contribution from carbon.