Enhanced Cycling and Structure Stability of an Electron Transfer-Accelerating Polymer Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate)-Covered Mn-Based Layered Cathode with Ga 3+ Doping for a Li-Ion Battery.

Mn-based cathode material Li 1.20 Mn 0.52 Ni 0.20 Co 0.08 O 2 was proposed and ameliorated by surface-coating poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and doping Ga 3+ . X-ray diffraction and high-resolution transmission electron microscopy studies revealed that part of Ga 3+ replacing the Ni site could reduce the Li + /Ni 2+ mixing by forming a well-ordered layered structure and a homogeneous coating layer of PEDOT:PSS is covered on the surface of Li 1.20 Mn 0.52 Ni 0.19 Co 0.08 Ga 0.01 O 2 . The results of the electrochemical studies demonstrated the higher initial charging-discharging Coulombic efficiency, and outstanding rate capabilities and cyclic performance were obtained for the PEDOT:PSS-covered and Ga 3+ -doped samples. Especially, 2 wt % PEDOT:PSS-coated Li 1.20 Mn 0.52 Ni 0.19 Co 0.08 Ga 0.01 O 2 delivered 38.3 mAh g -1 , which is larger than the pristine cathode at a 5C high rate. Meanwhile, it could retain 189.6 mAh g -1 (90.3% of its initial discharge capacity at 45 °C) after 300 cycles with a 1C rate, while the pristine cathode only delivered 149.7 mAh g -1 with 80.7% cycling retention left. The results strongly suggested that such PEDOT:PSS-coated and Ga 3+ -doped Mn-based layered structure materials demonstrated high potential as a cathode candidate especially for high-energy applications.