Porous nanoparticles-constructed granule LiMn2O4 spinel was achieved by a solid-state reaction at a relatively low temperature of 600°C, using a highly reactive Mn3O4 as manganese source, prepared by a precipitation-oxidation process. The granule LiMn2O4, well-crystallized with negligible oxygen deficiency, combines the advantages of nano-structured and bulk materials, exhibiting excellent electrochemical performance and a high tap density of 2.05gcm−3. Importantly, its cycling performance, especially at elevated temperatures, compares favorably with that of the doped or surface-coated LiMn2O4 materials reported. Also, it shows superior rate capability and cycling performance to the dispersive nanoparticle LiMn2O4 synthesized under the same conditions. The granule LiMn2O4 exhibits a discharge capacity of 121mAhg−1 at a current rate of 1C (where 1C=148mAg−1), and retains a capacity of 103mAhg−1 at 15C, showing 85% capacity retention. After 200 cycles at 1C and 25°C, it delivers a capacity of 119mAhg−1, retaining 98% of its initial capacity. After 100 cycles at 1C and 55°C, it shows a capacity of 114mAhg−1, preserving 95% of its initial capacity. Due to its excellent electrochemical performance and facile synthesis process adopted, the granule LiMn2O4 can serve as a promising cathode for high-performance Li-ion batteries.