Noncovalent interactions engineering construct the fast-kinetics organic cathode for room/low-temperature aqueous zinc-ion battery

Abstract

Electroactive organic electrode materials are receiving increasing attention in aqueous zinc-ion batteries (AZIBs). However, the insufficient electrical conductivity, sluggish kinetics and intrinsic soluble trait of organic molecules still hinder their application as the electrode material. Here, a carbonyl compound, dibenzo[b,i]thian threne-5,7,12,14-tetraone (DTT) is tightly wrapping by reduced graphene oxide (r-GO) with noncovalent interactions to obtain DTT@r-GO organic cathode material. Benefiting from the π-π coupling, the composite electrode delivers higher surface area, enhanced electron/ion transportation and stable structure, which exhibits superior rate performance (259.1 mAh g−1 at 0.1 A g-1 and 117.7 mAh g−1 at 10 A g−1) and considerable calendar life (4000 cycles with 100 % capacity retention at 10 A g−1). Electrochemical testing and ex-situ analysis prove CO can act as a strong electron donor together with co-accommodation of Zn2+/H+, theoretical calculation confirms the favorable two-step Zn storage configuration during the charge storage process. Furthermore, these AZIBs can steadily power electronic devices at −50 °C, as well as retain a high reversible capacity of 199.5 mAh g−1 at 50 mA g−1 and 100 % capacity retention after 3700 cycles at −20 °C. The work is believed to broaden the insight into noncovalent interactions and inspire the organic electrochemical materials.