Molecular Design of Electron-Rich Polyoxometalates Based Clusters Enabling Intelligent Energy Storage.

Abstract

The fabrication of molecular cluster-based intelligent energy storage systems remains a significant challenge due to the intricacies of multifunctional integration at the molecular level. In this work, low-valent metal atoms are successfully encapsulated within ɛ-type Keggin structures, yielding a novel cluster denoted as CuMo₁₆. This unique structure displayed the characteristic "molybdenum red" coloration, with a high degree of reduction (76.47%), which played a pivotal role in enhancing its electrochemical properties. The specialized configuration significantly enhanced multi-proton-coupled electron transfer kinetics, enabling efficient and rapid electron storage and release, with up to thirteen electrons per molecule. To construct an intelligent energy storage device, CuMo₁₆ is employed as a proton-coupled electron-active material and embedded within a polyvinyl alcohol (PVA) matrix, resulting in the flexible, wearable, rechargeable devices. The flexible electronics not only demonstrate real-time human motion detection but also exhibit remarkable energy storage performance, reaching a peak capacity of 194.19 mAh g^-1 and maintaining 68.2% capacity retention after 2500 cycles. Molecular dynamics simulations reveal that integrating CuMo₁₆ significantly enhances the intelligent storage performance of flexible electronics, and molecular regulation of CuMo₁₆ content provides an effective strategy for optimizing flexible electronic devices. This study lays the foundation for the development of cluster-based intelligent energy storage systems.