A Hybrid Energy Storage Mechanism of Zinc Hexacyanocobaltate-Based Metal–Organic Framework Endowing Stationary and High-Performance Lithium-Ion Storage

Abstract

Lithium-ion batteries (LIBs) are considered to be theoretically promising with regard to large-scale energy storage and conversion systems. However, a significant problem is the lack of cost-efficient high-performance cathode materials for LIBs. In this study, we demonstrate a Prussian blue analog, zinc hexacyanocobaltate (ZnHCCo), as the low-cost and high-performance cathode material for LIBs. The open-framework crystal structure of ZnHCCo contributes toward reversible cation insertion and extraction along with the spontaneous valence change of hosts. Specifically, the as-prepared ZnHCCo exhibits a highly reversible capacity of 121.5 mAh g−1 at a current density of 1.25 C, a superior rate capability of 60.5 mAh g−1 at 6.25 C, and a stable cycling stability with a Coulombic efficiency of 96.5%. Therefore, the well-crystallized and low-cost ZnHCCo is expected to be a potential cathode material for LIBs used in grid-scale energy storage and conversion systems. In addition, the synthesis process of the electrode material can be readily up scaled using the earth abundant and environmentally benign precursors via a room-temperature wet-chemical method.