Hidehiko Tajima

Layered Polyaniline Composites with Cation‐Exchanging Properties for Positive Electrodes of Rechargeable Lithium Batteries

Layered polyaniline/polyaniline-polyanion composite films (PAn-X/PAn-PA) were synthesized by electrochemical oxidation of aniline in aqueous acid solutions (HCl, HClO[sub 4]) followed by polymerization in poly(styrene-4-sulfonic acid) (PSSH) solutions. The films consist of inner polyaniline (PAn) layers doped with smaller size anions (X) and outer PSS-doped PAn layers. The resulting films showed high redox activities with cation-transfer properties in organic electrolyte solutions. The improved charge/discharge characteristics of the composite films gave an expectation of higher energy density for the full cell with lithium negative electrode.

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.