Polyaniline nanoarrays/carbon cloth as binder-free and flexible cathode for magnesium ion batteries

Abstract

• The reversible storage of Mg 2+ in PANI at non-aqueous MIBs was first proved. • The binder-free flexible cathode was prepared by simple in-situ polymerization. • The CC stabilized the structure and improved conductivity of the cathode. • The double-ion storage mechanism provides capacity for the PANI/CC. • The capacity retention of 97.25% was obtained after 1500 cycles at 1 A g −1 . Magnesium ion batteries (MIBs) attracted much attention in recently years due to the advantages of high theoretical capacity and low cost. However, the strong polarization effect of Mg 2+ cause slow diffusion rate, hindering the development of MIBs. Herein, we designed and synthesized a binder-free polyaniline array/carbon cloth (PANI/CC) as cathode for MIBs. Given the benefit of improved electrical conductivity and alleviated agglomeration, the cathode exhibits enhanced electrochemical performance compared with the pure polyaniline cathode in MIBs. The PANI/CC cathode displays the highest specific capacity of 219 mA h g −1 at 200 mA g −1 and the capacity retention of 97.25% after over 1500 cycles at 1 A g −1 . Then, the reversible redox transformation between quinone rings and benzene rings during charging and discharging process was demonstrated by the ex-situ X-ray photoelectron spectroscopy (XPS) and ex-situ Raman spectra. In addition, PANI/CC shows an initial capacity of 75 mA h g −1 at 50 mA g −1 in PANI/CC //Mg(TFSI) 2 // MNTO full cell. Our work demonstrates that PANI/CC is a promising cathode for MIBs, which may offer new insight for the development for high-performance MIBs.