Improved Li-storage performance with PEDOT-decorated MnO₂ nanoboxes

In this paper, MnO₂ nanoboxes coated with poly(3,4-ethylenedioxythiophene) film (denoted as MnO₂@PEDOT) are investigated as an anode material in lithium-ion batteries. The MnO₂ nanoboxes are developed through the surface chemical oxidation decomposition of MnCO₃ cubes and the subsequent removal of their remaining cores. PEDOT is coated on the surface of MnO₂ nanoboxes via in situ polymerization of 3,4-ethylenedioxythiophene. The charge-discharge tests demonstrate that this special configuration endows the resulting MnO₂@PEDOT with remarkable electrochemical performances, that is a reversible capacity of 628 mA h g^-1 after 850 cycles at a current density of 1000 mA g^-1 and a rate capacity of 367 mA h g^-1 at 3000 mA g^-1. The results indicate that the nanoboxes provide the paths for Li-ion diffusion, the reaction sites for Li-ion intercalation/deintercalation and the space to buffer the volume change during the charge-discharge process, while the conductive polymer ensures the structural stability and improves the electronic conductive property of MnO₂.