High‐Performance Aqueous Rechargeable K/Zn Hybrid Batteries Based on Berlin Green Cathode Materials

Abstract

Aqueous rechargeable zinc-based batteries with the advantages of sustainability, safety, and low cost, are suitable for large-scale electrochemical energy storage applications. In this work, aqueous zinc-based batteries with low defect Berlin green (FeHCF) cathode, a hybrid zinc triflate and potassium triflate electrolyte, and zinc anodes are developed. In the hybrid electrolyte, the K + ions with the weak solvation effect and small electrostatic interaction are the dominant intercalation species in the FeHCF, resulting in the fast charge transfer process and rapid diffusion kinetics. The Zn 2 + ions stay at the surface rather than penetrate into the bulk phase. Thus, the hybrid batteries deliver a high specific capacity of 169.2 mAh g À 1 at 100 mA g À 1 , excellent rate performance with 45.7 mAh g À 1 at 6 A g À 1 , and good long-term cyclability with a capacity retention of 57 % over 1000 cycles at 1 A g À 1 . The results suggest using aqueous K/Zn hybrid electrolytes can improve the electrochemical performance of FeHCF.

Turning Berlin green frameworks into cubic crystals for cathodes with high-rate capability

“…, pre-lithiation with lithium/perylene/dimethoxyethane solution). Moreover, our approach would considerably reduce the generation of toxic wastes, 13,27,33–38,46 thereby indicating the greener aspect of our synthetic protocol.…”

“…The successful synthesis of a series of BG samples was supported by the low K/Fe molar ratio calculated based on the results of inductively coupled plasma optical element spectroscopy (ICP-OES, Table S1 †). Compared with conventional synthetic methods, 13,27,[33][34][35][36][37][38]46 our approach provides a greener alternative because of its mild synthetic conditions and the absence of strong acids (e.g., hydrochloric acid), energy-consuming processes (e.g., hydrothermal process), and post-treatment (e.g., pre-lithiation with lithium/perylene/dimethoxyethane solution). Moreover, our approach would considerably reduce the generation of toxic wastes, 13,27,[33][34][35][36][37][38]46 thereby indicating the greener aspect of our synthetic protocol.…”

“…The successful synthesis of a series of BG samples was supported by the low K/Fe molar ratio calculated based on the results of inductively coupled plasma optical element spectroscopy (ICP-OES, Table S1†). Compared with conventional synthetic methods, 13,27,33–38,46 our approach provides a greener alternative because of its mild synthetic conditions and the absence of strong acids ( e.g. , hydrochloric acid), energy-consuming processes ( e.g.…”

“…The aforementioned crystallization proceeds rapidly in a random manner, scarcely allowing for the possibility of controlling its morphology. 31,32 Furthermore, previous strategies engaging chelating agents 13,33,34 and hydrothermal processes 27,[34][35][36][37][38] cannot achieve BG cubes because alkali ions could be readily incorporated into the BG framework, thus resulting in the formation of either PB or PW phases rather than the BG phase.…”

Design of Inorganic–Organic Hydrophobic Coating on Zn Anode Realizes Highly Reversible and Dendrite‐Free Zn‐Ion Batteries

“…[1][2][3] However, the cycle stability is seriously constrained due to dendrite growth and side reactions during Zn plating/stripping process. [4][5][6] These two issues are the main reasons for the failure and electrochemical performance decrease of ZIBs. [7,8] Therefore, to ensure the wider application of ZIBs, it is urgent to solve the issues of dendrite growth and side reactions.…”