Xia Jiale, Wang Zeyi, Rodrig Nuwanthi D, Nan Bo, Zhang Jiaxun, Zhang Weiran, Lucht Brett L, Yang Chongyin, Wang Chunsheng
Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD, 20742, USA.
Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China.
Adv Mater. 2022 Oct;34(43):e2205229. doi: 10.1002/adma.202205229. Epub 2022 Sep 25.
Copper fluoride (CuF ) has the highest energy density among all metal fluoride cathodes owing to its high theoretical potential (3.55 V) and high capacity (528 mAh g ). However, CuF can only survive for less than five cycles, mainly due to serious Cu-ion dissolution during charge/discharge cycles. Herein, copper dissolution is successfully suppressed by forming Cu -coordinated sodium alginate (Cu-SA) on the surface of CuF particles during the electrode fabrication process, by using water as a slurry solvent and sodium alginate (SA) as a binder. The trace dissolved Cu in water from CuF can in situ cross-link with SA binder forming a conformal Cu-SA layer on CuF surface. After water evaporation during the electrode dry process, the Cu-SA layer is Li-ion conductor but Cu insulator, which can effectively suppress the dissolution of Cu-ions in the organic 4 m LiClO /ethylene carbonate/propylene carbonate electrolyte, enhancing the reversibility of CuF . CuF electrode with SA binder delivers a reversible capacity of 420.4 mAh g after 50 cycles at 0.05 C, reaching an energy density of 1009.1 Wh kg . Cu cross-link polymer coating on CuF opens the door for stabilizing the high-energy and low-cost CuF cathode for next-generation Li-ion batteries.
氟化铜（CuF）在所有金属氟化物阴极中具有最高的能量密度，这归因于其高理论电位（3.55 V）和高容量（528 mAh g）。然而，CuF只能循环不到五次，主要是由于在充放电循环过程中严重的铜离子溶解。在此，通过在电极制造过程中，以水作为浆料溶剂，海藻酸钠（SA）作为粘结剂，在CuF颗粒表面形成铜配位海藻酸钠（Cu-SA），成功抑制了铜的溶解。CuF中微量溶解在水中的铜可以与SA粘结剂原位交联，在CuF表面形成保形的Cu-SA层。在电极干燥过程中水分蒸发后，Cu-SA层是锂离子导体但铜绝缘体，它可以有效抑制铜离子在4 m LiClO/碳酸亚乙酯/碳酸丙烯酯有机电解质中的溶解，增强了CuF的可逆性。使用SA粘结剂的CuF电极在0.05 C下循环50次后，可逆容量为420.4 mAh g，能量密度达到1009.1 Wh kg。CuF上的铜交联聚合物涂层为稳定下一代锂离子电池的高能量和低成本CuF阴极打开了大门。
