A free-sealed high-voltage aqueous polymeric sodium battery enabling operation at −25°C

• Published in: Cell reports physical science Vol. 3; no. 3; p. 100805
• Main Authors: Rong, Jing-Zhi, Cai, Tian-Xun, Bai, Yu-Zhou, Zhao, Xun, Wu, Tong, Wu, Ying-Kang, Zhao, Wei, Dong, Wu-Jie, Xu, Shu-Mao, Chen, Jun, Huang, Fu-Qiang
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 16.03.2022; Elsevier
• Subjects: aqueous polymeric sodium batteries; fluorine doping; free seal; high rate; high voltage; hydrogen bonding; low temperature; P2-type cathode; ultrathin; water in ionogel; free seal; hydrogen bonding; aqueous polymeric sodium batteries; high rate; fluorine doping; P2-type cathode; high voltage; ultrathin; low temperature; water in ionogel
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2022.100805

An increasing demand for electric vehicles and flexible electronics focuses attention on developing a safe, high-energy, and sustainable battery that can work under severe conditions. Emerging high-voltage aqueous batteries based on highly concentrated salts and molecular crowding electrolytes are likely to be hampered by their poor low-temperature performance because of a high freezing point and salting out at low temperature. Inspired by the antifreezing ionogel electrolyte for transport measurements at subzero temperatures, we design a water-in-ionogel electrolyte with a low salt-concentration (2m NaTFSI) and high operational voltage (3.0 V) by changing the hydrogen bonding and introducing fluoride additives for low-temperature operation. A full cell with a P2-type Na2/3Mn2/3Co1/3O1.98F0.02 cathode and hard-carbon anode could deliver high energy densities of 109 and 23.4 Wh kg−1 at room temperature and −25°C. This eco-friendly aqueous polymeric battery could be free sealed and perform in water. This work opens an avenue for designing high-energy, free-sealed aqueous batteries for low-cost, sustainable energy storage, enabling subzero temperature operation. [Display omitted] •F-containing water-in-ionogel electrolyte enables high-voltage, low-temperature operation•F doping endows Mn-based P2-type cathodes with enhanced hydrophilicity and rate performance•The fabricated aqueous polymeric sodium-ion battery enables subzero temperature operation•The free-sealed battery can work under severe condition with advantage in weight Rong et al. demonstrate that a water-in-ionogel (WIG) electrolyte with low salt concentration (2m NaTFSI) and high operational voltage (3.0 V) can rival the high voltage of typical “water-in-salt” and “molecular crowding” electrolytes. The WIG electrolyte, exhibiting superior antifreezing properties without salting out at low temperature and high stability against sodium metal, is a promising candidate for aqueous polymeric batteries.