The Gao group from Beihang University, China, carried out the experiments with a 50 mL autoclave. The scientists chose CH3COOLi, H3PO4 and the inexpensive FeSO4 as a source for lithium, iron and PO4. Glycol was used as a solvent. By adjusting the mole ratio of lithium, iron and PO4 to an appropriate value, hierarchical LiFePO4/C microspheres were formed after the hydrothermal reaction and subsequent carbon coating process.

Characterization revealed that the LiFePO4/C microspheres are uniform with a particle size of 8–10 µm and composed of densely compacted nanosheets with a thickness of 20–30 nm. The gaps between the nanosheets are estimated to be 10 50 nm.

The tap density of the LiFePO4/C composite reaches up to 1.5 g cm–3, which the team attributes to the micro-sized spherical morphology and closely packed primary nanosheets.

As cathode material for lithium-ion batteries, the composite exhibits a high capacity: 155 mAh g–1, 144 mAh g–1, 129 mAh g–1, and 104 mAh g–1 at 0.1 C, 1 C, 5 C and 10 C, respectively. The high performance of the electrode is related to the facile electrolyte infiltration and the short lithium ion transport pathways of the LiFePO4/C microspheres.

Full details can be found in the journal Nanotechnology.