3D Covalent Polyoxovanadate‐Organic Framework as an Anode for High‐Performance Lithium‐Ion Batteries

Abstract

Polyoxometalates (POMs), as a unique class well‐defined metal‐oxo clusters with excellent multielectron redox properties, have attracted extensive attention in the field of energy storage and conversion, but it is still challenging to achieve their highly uniform and stable monodispersed. In this study, for the first time, polyoxovanadate (POV) is used, (NH₄)₂[V^IV₃V^V₃O₁₀{NH₂C(CH₂O)₃}₃] (tris‐V₆O₁₉), as nodes and successfully obtain a 3D covalent polyoxovanadate‐organic framework through a green hydrothermal synthesis method, termed POF‐1. Total scattering atomic pair distribution function analysis confirms that POF‐1 has a noninterpenetrated diamond‐like framework, fully exposing the monodispersed tris‐V₆O₁₉, effectively utilizing the active components of V^IV/V^V and enhancing surface mass transfer. Notably, POF‐1 demonstrates exceptional performance in lithium‐ion batteries, achieving a high reversible capacity of 887.4 mAh g⁻¹ at 0.1 A g⁻¹ and retaining over 92% capacity at 1 C during 1000 cycles. Electrochemistry mechanism and density functional theory calculations reveal that V centers in tris‐V₆O₁₉ and carbonyls (C═O) in BDOEB linkers are the main active sites, with each POF‐1 fragment capable of storing up to 14 Li⁺. This study opens a new pathway for the efficient and green synthesis of new 3D well‐defined POM‐organic frameworks, and shows great application prospect in the field of energy storage.