Raising the cycling stability of aqueous lithium-ion batteries by eliminating oxygen in the electrolyte.
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.
Luo
Jia-Yan
JY
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, Fudan University, Shanghai 200433, China.
Cui
Wang-Jun
WJ
He
Ping
P
Xia
Yong-Yao
YY
D011211:Electric Power Supplies; D004563:Electrochemistry; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*
D004573:Electrolytes; D008094:Lithium; D010100:Oxygen