High‐Power and Ultrastable Aqueous Calcium‐Ion Batteries Enabled by Small Organic Molecular Crystal Anodes

• DOI: 10.1002/adfm.202214304
• Publication Date: 2023-04-19T03:55:32Z
• Authors: Renjie Li; Jingya Yu; Feiyang Chen; Yaqiong Su; Kang Cheung Chan; Zheng‐Long Xu
• Keywords: Prussian blue

Abstract Calcium ion batteries (CIBs) are pursued as potentially low‐cost and safe alternatives to current Li‐ion due the high abundance of calcium element. However, large divalent nature Ca 2+ leads strong interaction with intercalation hosts, sluggish diffusion kinetics low power output. Herein, a small molecular organic anode is reported, tetracarboxylic diimide (PTCDI), involving carbonyl enolization (CO↔CO − ) in aqueous electrolytes, which bypasses difficulties intercalation‐type electrodes avoid capacity sacrifice for polymer electrodes, thus manifesting rapid storage capacities. In an Ca‐ion cell, PTCDI presents reversible 112 mAh g −1 , high‐capacity retention 80% after 1000 cycles high‐power capability at 5 A rival state‐of‐the‐art materials CIBs. Experiments simulations reveal that ions diffusing along axis tunnel enolize groups without being entrapped aromatic carbon layers. The feasibility anodes practical CIBs demonstrated by coupling cost‐effective Prussian blue analogous cathodes CaCl 2 electrolyte. appreciable performance crystals will spur development green