Edge-Rich Multidimensional Frame Carbon as High-Performance Electrode Material for Vanadium Redox Flow Batteries

The low electrocatalytic activity of pristine graphite felt (GF) electrodes toward V(II)/V(III) and V(IV)/V(V) redox couples is a major concern in vanadium redox flow batteries (VRFBs). For overcoming this challenge, herein a novel composite electrode is proposed comprising of two components: multidimensional frame carbon (MFC) derived from edge-rich carbon and GF that serves as the frame for the in situ growth of MFC. The high electrocatalytic activity, rapid charge migration, and reduced local current emanating from the 0D, 2D, and 3D coexistent structures of the MFC material, respectively, enhance the performance of the GF. Consequently, the battery assembled using the MFC GF electrode achieves a maximum current density of 500 mA cm(-2), along with high stability and preeminent energy efficiency at a current density of 200 mA cm(-2) for over 400 cycles. For the first time via density functional theory analysis on VRFBs, this study reveals that the edge-rich carbon atoms possess higher electrocatalytic activity in both positive and negative electrolytes than the plane carbon atoms and heteroatoms. Therefore, this study is of immense significance in guiding and promoting the application of edge-rich carbon in the battery-based energy storage industry.