I n this study, we report that Berlin Green (FeFe-BG) framework exhibits superior performance in the catalytic coupling of carbon disulfide (CS 2 ) and propylene oxide (PO) to generate a random copolymer containing thioether, propylene monothiocarbonate and ether units. Oxygen and sulfur atom exchange was detected in polymeric and cyclic thiocarbonate byproducts and utilized to modulate the copolymerization of CS 2 and propylene oxide. The coupling of PO and CS 2 was selective for copolymer formation under various reaction conditions. 1 H and 13 C NMR spectroscopy determined two distinct polymer linkages and two cyclic byproducts. Copolymer number average molecular weights ranged from 6.4 kg/mol to 10.5 kg/mol, with a comparatively low polydispersity of 1.3–1.7. The CS 2 /PO molar feed ratio had a significant impact on the O/S exchange process; the ratio of cyclic thiocarbonate byproducts could be efficiently regulated by tuning the CS 2 molar feed ratio.
Gang Ni,Zhao Hao,Guo Yin Zou,Fu Hu Cao,Ling Qin,Cheng Gang Zhou
Graphical An aqueous Zn-based battery with a Berlin green cathode, a K/Zn hybrid electrolyte, and a zinc metal anode are developed. Owing to the rapid insertion and transportation of K ions in the cathode materials and the good compatibility of electrolytes to the metal anode, the hybrid battery delivers improved rate capability and cycle performance. : 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 −1 at 100 mA g −1 , excellent rate performance with 45.7 mAh g −1 at 6 A g −1 , and good long-term cyclability with a capacity retention of 57 % over 1000 cycles at 1 A g −1 . The results suggest using aqueous K/Zn hybrid electrolytes can improve the electrochemical performance of FeHCF.
Rechargeable Fe-ion batteries with overwhelming cost/environmental benign superiorities hold great promise in large-scale charge-storage applications. However, there is still a lack of competitive cathodes with prominent capacity and long-term cyclability. To overcome these constraints, a unique Fe 2+ /NH 4 + co-insertion strategy is proposed, enabling both doubled reversible capacity and cyclic life of Berlin green (FeHCF) cathodes. The Fe 2+ insertion proves to induce FeHCF lattice contractions, alter ligand environment/activation energies of low-spin Fe III, and hence boost the redox conversion depth, while NH 4 + co-insertions help to elevate the cathode capacities by utilizing Fe 2+ -unoccupied reaction sites. Besides, they generate hydrogen bonds between inserted NH 4 + ions and N atoms in FeHCF, capable of vastly strengthening the cathode's cyclic durability. Cathodes in such collaborative dual-cation electrolytes exhibit a remarkable capacity of 162 mAh g −1 (4 A g −1 ) and far prolonged operation lifespan (over 1000 cycles) when compared to single-cation cases. The assembled full cells demonstrate impressive energy densities up to 70.4 Wh kg −1 , and far superior capacity retention of 88% after all the cycling. This work may offer a simple/feasible, and effective route to render high-capacity and long-lasting cathodes for future/practical Fe-ion battery systems.
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