A Membrane‐Free Rechargeable Seawater Battery Unlocked by Lattice Engineering

• Published in: Advanced materials (Weinheim) Vol. 36; no. 30; pp. e2312343 - n/a
• Main Authors: Wen, Wei, Geng, Chao, Li, Xinran, Li, Hongpeng, Wu, Jin‐Ming, Kobayashi, Hisayoshi, Sun, Tulai, Zhang, Zhenyu, Chao, Dongliang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-07-2024
• Subjects: Anatase; aqueous batteries; Aqueous electrolytes; aqueous Na‐ion batteries; Calcium ions; Cations; Density functional theory; Diffusion barriers; Electrolytes; Energy storage; lattice expansion; Primary batteries; Product safety; Rechargeable batteries; Seawater; seawater batteries; Titanium dioxide; seawater batteries; lattice expansion; aqueous batteries; titanium dioxide; aqueous Na‐ion batteries
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202312343

Seawater batteries that directly utilize natural seawater as electrolytes are ideal sustainable aqueous devices with high safety, exceedingly low cost, and environmental friendliness. However, the present seawater batteries are either primary batteries or rechargeable half‐seawater/half‐nonaqueous batteries because of the lack of suitable anode working in seawater. Here, a unique lattice engineering to unlock the electrochemically inert anatase TiO2 anode to be highly active for the reversible uptake of multiple cations (Na+, Mg2+, and Ca2+) in aqueous electrolytes is demonstrated. Density functional theory calculations further reveal the origin of the unprecedented charge storage behaviors, which can be attributed to the significant reduction of the cations diffusion barrier within the lattice, i.e., from 1.5 to 0.4 eV. As a result, the capacities of anatase TiO2 with 2.4% lattice expansion are ≈100 times higher than the routine one in natural seawater, and ≈200 times higher in aqueous Na+ electrolyte. The finding will significantly advance aqueous seawater energy storage devices closer to practical applications.
A new rechargeable seawater battery that directly utilizes natural seawater as both anolyte and catholyte is successfully constructed. The lattice expansion strategy transforms electrochemically inert anatase TiO2 into a high‐specific‐capacity anode in various aqueous electrolytes. This approach effectively addresses the anode challenge in rechargeable seawater batteries, which opens new perspectives for designing high‐energy and scalable aqueous batteries with seawater.