Charge/discharge characteristics of polyaniline-based polymer composite positives for rechargeable lithium batteries

The structure of a polyaniline-poly(styrene-4-sulfonate) (PAn-PSS) composite film was optimized as the positive electrode for rechargeable lithium batteries to improve the charge/discharge characteristics in organic electrolyte solutions. The composite films prepared in aqueous poly(styrene-4-sulfonic acid) (PSSH) solutions containing small amounts of HClO4 showed higher charge/discharge capacities than those prepared in PSSH without HClO4. However, the utilization of Li+-ion transport in the redox process decreased with an increase in the HClO4 concentration. A stacked PAn-ClO4/PAn-PSS film, which consists of an inner PAn layer doped with smaller size anion (ClO4−) and an outer PAn-PSS composite layer, was prepared by the electrolysis of aniline in aqueous HClO4 followed by the polymerization in a PSSH solution. The resulting films gave improved charge/discharge characteristics in organic electrolyte solutions and lead to higher energy density of the full cell with lithium negative electrode.