Three-dimensional carbon nanotubes-encapsulated Li2FeSiO4 microspheres as advanced positive materials for lithium energy storage

Polyanion-type Li2FeSiO4 has been considered as an advanced positive material for lithium energy storage owing to the low cost, good safety and high theoretical capacity. Unfortunately, the inferior electrical conductivity and bad diffusivity of Li+ inhibit its widespread applications for lithium energy storage. In the present research, we have used the simple spray-drying route to fabricate the three-dimensional carbon nanotubes (3D CNTs) encapsulated Li2FeSiO4 microspheres (3D-Li2FeSiO4/CNTs). Benefiting from the interconnected conducting networks, the as-fabricated 3D-Li2FeSiO4/CNTs cathode displays superior battery property with a specific capacity of 169.1 mAh g(-1) at 0.1C. Besides, it also delivers a discharge capacity of 104.1 mAh g(-1) at 5C over 500 cycles with a capacity retention ratio of around 91.2%. The above results suggest that the designed 3D-Li2FeSiO4/CNTs composite is an advanced positive material in lithium energy storage.