Nanoscale Engineering of Graphene‐Viologen Based 3D Covalent Organic Polymer Interfaces Leading to Efficient Charge‐Transfer for Pseudocapacitive Energy Storage

Viologen based covalent organic polymer (COP) interfaced with graphene at the nanoscale showed pseudocapacitive energy storage associated with redox-active moieties. The positively charged viologen moieties endow charge storage as well as easy wetting of the electrode. The non-conducting COP grown over conducting graphene enhances its performance by extensive interface formation. All the redox states of viologen moieties can be reversibly attained without significant polarization when it is interfaced with graphene. However, the COP (devoid of graphene) shows irreversible/pseudo-reversible behavior due to lack of electron conducting pathways. The intimate and dense conducting pathways in graphene-COP composites facilitates the charge transfer across interface leading to effective and reversible participation of redox moieties across the entire range over 1000 cycles. Also, we show that the strategy being universal in nature and aid in electron transfer in dense 3D networks which lacks traditional pi-pi stacking of 2D crystalline networks (COF).