To overcome the disproportionation reaction and Jahn-Teller distortion of Mn3+ in LiMn2O4 cathode materials, we demonstrate a facile route to synthesize hierarchical porous Li4Mn5O12 nano/micro structure, which consists of numerous well-crystallized nanoparticles with diameters of 20–30 nm. The unique structure combines the advantages of both nanostructure and microstructure. When applied as cathode materials for Li-ion batteries, it exhibited a very high specific capacity of 161 mAh g−1 (theoretical value: 163 mAh g−1) with intriguing rate performance and cycling stability.