Lithium‐Ion‐Based Electrochemical Energy Storage in a Layered Vanadium Formate Coordination Polymer.

A vanadium formate (VF) coordination polymer and its composite with partially reduced graphene oxide (prGO), namely VF‐prGO, can be applied as anode materials for Li‐ion based electrochemical energy storage (EcES) systems in the potential range of 0–3 V (vs Li+/Li). This study shows that a reversible capacity of 329 mAh g−1 at a current density of 50 mA g−1 after 50 cycles can be realized for VF along with a high rate capability. The composite exhibits even a higher capacity of 504 mAh g−1 at 50 mA g−1. A good capacity retention is observed even after 140 cycles for both VF and the composite. An ex‐situ X‐ray photoelectron spectroscopy study indicates the involvement of V3+/V4+ redox couple in the charge storage mechanism. A significant contribution of this reversible capacity is attributed to the pseudocapacitive behavior of the system. [ABSTRACT FROM AUTHOR]