Improvement of cycling performance of Na_2/3Co_2/3Mn_1/3O₂ cathode by PEDOT/PSS surface coating for na ion batteries

The surface-modified Na_2/3Co_2/3Mn_1/3O₂ is coated with a conductive Poly (3,4-Ethylene dioxy thiophene)-poly (styrene sulfonate) (PEDOT/PSS) polymer, and their resulting electrochemical properties were investigated as Na-ion battery cathode. The surface-modified Na_2/3Co_2/3Mn_1/3O₂ cathode material exhibits a high discharge capacity and good rate capability due to enhanced electron transport by surface PEDOT/PSS. The presence of PEDOT/PSS surface layer suppresses the growth of a resistive layer, while the dissolution of transition metals of the active cathode materials is inhibited as well. The resulting surface-modified Na_2/3Co_2/3Mn_1/3O₂ shows superior cycling performance, which is much stable than the pristine one as being the Na-ion battery cathode.