Synergistically Constructed Lamination-like Network of Redox-active Polyimide and MXene via π-π interactions for Aqueous Storage

Abstract

As a nonmetallic charge carrier, ammonium ion () has garnered significant attention in the construction of aqueous batteries due to its advantages of low molar mass, small hydration size and rapid diffusion in aqueous solutions. Polymers are a kind of potential electro-active materials for aqueous storage. However, traditional polymer electrodes are typically created by covering the bulky collectors with excessive additives, which could lead to low volume capacity and unsatisfactory stability. Herein, a nanoparticle-like polyimide (PI) was synthesized and then combined with MXene nanosheets to synergistically construct an additive-free and self-standing PI@MXene composite electrode. Significantly, the redox-active PI nanoparticles are enclosed between conductive MXene flakes to create a 3D lamination-like network that promotes electron transmission, while the π-π interactions existing between PI and MXene contribute to the enhanced structural integrity and stability within the composite electrode. As such, it delivers superior aqueous storage behaviors in terms of a notable specific capacity of 110.7 mAh cm–3 and a long lifespan with only 0.0064% drop each cycle. Furthermore, in-situ Raman and UV-vis examinations provide evidence of reversible and stable redox mechanism of the PI@MXene composite electrode during uptake/removal, highlighting its significance in the area of electrochemical energy storage.