Raising the cycling stability of aqueous lithium-ion batteries by eliminating oxygen in the electrolyte

• Published in: Nature chemistry Vol. 2; no. 9; pp. 760 - 765
• Main Authors: Luo, Jia-Yan, Cui, Wang-Jun, He, Ping, Xia, Yong-Yao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-09-2010; Nature Publishing Group
• Subjects: 639/301/299/161/891; 639/638/298; Acids; Analytical Chemistry; Batteries; Biochemistry; Carbon; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Electric Power Supplies; Electrochemistry; Electrodes; Electrolytes; Electrolytes - chemistry; Energy storage; Flammability; Inorganic Chemistry; Lead; Lithium; Lithium - chemistry; Nickel; Organic Chemistry; Organic solvents; Oxygen; Oxygen - chemistry; Physical Chemistry; Retention; Safety; Solvents
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.763

Aqueous lithium-ion batteries may solve the safety problem associated with lithium-ion batteries that use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries such as lead-acid and nickel-metal hydride systems. But all reported aqueous lithium-ion battery systems have shown poor stability: the capacity retention is typically less than 50% after 100 cycles. Here, the stability of electrode materials in an aqueous electrolyte was extensively analysed. The negative electrodes of aqueous lithium-ion batteries in a discharged state can react with water and oxygen, resulting in capacity fading upon cycling. By eliminating oxygen, adjusting the pH values of the electrolyte and using carbon-coated electrode materials, LiTi
2
(PO
4
)
3
/Li
2
SO
4
/LiFePO
4
aqueous lithium-ion batteries exhibited excellent stability with capacity retention over 90% after 1,000 cycles when being fully charged/discharged in 10 minutes and 85% after 50 cycles even at a very low current rate of 8 hours for a full charge/discharge offering an energy storage system with high safety, low cost, long cycling life and appropriate energy density.
Aqueous lithium-ion batteries have great potential as stationary power sources, but they have had problems with poor stability. A significant improvement in their cycling stability has been achieved by eliminating oxygen, adjusting the electrolyte pH values, and using a carbon-coated electrode material.