Spray drying-assisted synthesis of hollow spherical Li2FeSiO4/C particles with high performance for Li-ion batteries

•Li2FeSiO4/C composites are synthesized by spray drying-assisted method.•Li2FeSiO4/C composites form a hollow spherical structure.•Li2FeSiO4/C composite exhibits outstanding electrochemical performance.•The superior properties are due to the improved ionic/electronic conductivity.

Improving the rate performance is still a major challenge for Li2FeSiO4 cathode material for Li-ion battery. Herein, hollow spherical Li2FeSiO4/C microscale particles, consisting of carbon-coated primary nanoparticles (20–40 nm) have been fabricated by a spray drying-assisted method. The particle size of spherical Li2FeSiO4/C is 1–5 μm, which is suitable for commercial application. When used as a cathode material for Li-ion battery, the as-prepared Li2FeSiO4/C composite with 16.7 wt.% carbon exhibits a high discharge capacity of 165 mAh g− 1 at 0.2 C rate. At 0.5 C, 5 C and 10 C rates, the capacities of 151 mAh g− 1, 111 mAh g− 1, and 96 mAh g− 1 are observed, respectively, indicating superior rate performance. Meantime, good cycling stability is achieved with a capacity retention of 94.5% at a high current density of 2 C after 100 cycles. The excellent electrochemical performance is mainly ascribed to the improved ionic/electronic conductivity arising from the hollow spherical structure and carbon-coated primary nanoparticles. The spray drying process shows a great potential for the large scale production of high quality Li2FeSiO4/C composite.