ABSTRACT
A cost-effective quinone-pyrrole conjugated polymer is utilized as an electrode for non-aqueous Al, Zn and Li-ion batteries. Reversible capacities of 120 mA h g-1 at 50 mA g-1 for Al-ion batteries and 108 and 175 mA h g-1 for Zn and Li-ion batteries, respectively, at 100 mA g-1 are observed. Thousands of stable cycles were obtained at 1000 mA g-1 current density, providing sufficient evidence for a range of applications of the polymer in electrochemical energy storage.
ABSTRACT
Rechargeable magnesium batteries are of considerable interest due to their high theoretical capacity, and they are projected as good alternates for stationary energy storage and electric vehicles. Sluggish Mg2+ kinetics and scarce availability of suitable cathode materials are major issues hindering the progress of rechargeable magnesium batteries. Herein, a conjugated, off-planar, two-dimensional (2D) polymer is explored for reversible magnesium storage. The polymer cathode reveals high capacity and high cycling stability with high rate capability. Replacing the Mg metal anode with the Mg alloy, AZ31 further enhances the ion storage performance. At a high current density of 2 A g-1, stable capacity is shown for almost 5000 cycles with 99% Coulombic efficiency. A composite of carbon nanotube with the polymer delivers capacity values higher (>1.5 times) than that of a pristine polymer at a current density of 2 A g-1 and shows cycling up to 5 A g-1. Electrokinetic studies reveal a contribution of pseudocapacitive nature, and the mechanism is investigated by ex situ X-ray photoelectron spectroscopy and infrared spectroscopy. The use of 2D polymer electrodes opens up opportunities for developing high-rate, high-capacity, and stable rechargeable magnesium ion batteries.
