Metal ions addition as interfacial mediators toward improving the electrochemical performance of PANI-rGO aerogels

We report a simple and general strategy to optimize the composite of reduced graphene oxide (rGO) and polyaniline (PANI) via introducing a small quantity of divalent metal ions M (M = Ni2+, Co2+, Cu2+, Mn2+) as mediators. This simple approach can not only inhibit the aggregation of both the graphene sheets and the PANI nanoparticles, yielding a uniform PANI-rGO morphology with increased specific surface area, but also strengthen the utilization of the good conductivity of rGO, leading to reduced charge transfer resistance. The metal ions modified binary PANI-rGO aerogels (P-GA-Ms) exhibit all fairly high specific charges or capacities of 271 (Ni2+), 211(Co2+), 200 (Cu2+) and 181 mA h . g(-1) (Mn2+), at 1 A g(-1) in a three-electrode system, with an average retention of 93% over 10000 cycles of charge-discharge at 3 A g(-1). Additionally, as a proof of generality, a ternary system of MoS2-PANI-GA with additive Ni2+ showing better electrochemical performance than that without Ni2+ is demonstrated as well. This study provides a rational way on improving the specific charges or capacities of GA-based composites by adopting metal ions as mediators. (C) 2018 Elsevier Ltd. All rights reserved.