Mesoporous polythiophene birnessite (b)-MnO2 has been synthesized by a modified interfacial method to develop cathode electrode materials for lithium batteries. The N2 adsorption/desorption isotherm test of mesoporous polythiophene MnO2 shows a type IV hysteresis loop, which is characteristic of a mesoporous structure. Mesoporous polythiophene MnO2 has a high surface area of 226 m2 g−1 with a pore diameter of 5.2nm The mesoporous polythiophene b-MnO2 cathode electrode for Li-ion battery exhibited an initial discharge capacity of 305 mAh g−1 at a current density of 10mAg−1, which is almost equal to its theoretical capacity. When applying a current of 300mAg−1, mesoporous polythiophene MnO2 electrode shows the initial discharge capacity of 211 mAh g−1, which is 69% of its theoretical capacity. Mesoporous polythiophene MnO2 shows high capacity and good cycle stability even at high current densities due to its high surface area and fast Li-ion diffusion path.