Effect of carbon addition on Al2W3O12-based electrodes for lithium-ion batteries

Abstract

Abstract Al 2 W 3 O 12 belongs to the A 2 M 3 O 12 family of ceramics, which is known for its unique mechanical and thermal properties. Due to its low positive thermal expansion, this phase is a good candidate for applications that require high resistance to thermal shock. In addition, a strong interest in this ceramic family has recently emerged due to its low-density structure with a lot of empty spaces capable of storing alkaline ions. Therefore, these orthorhombic open-framework structures can be potentially useful as electrodes in lithium-ion batteries (LIBs). Here, Al 2 W 3 O 12 was synthesized by co-precipitation method and subsequently used as active material in LIBs, achieving a discharge capacity of 130 mA h g −1 at the 100 th cycle. Two post-synthesis routes were applied to add carbon phases to Al 2 W 3 O 12 , providing an additional mechanism to tune the energy delivered by LIB using Al 2 W 3 O 12 as the active material. The first route considered mechanical mixing of the as-obtained ceramic powder with graphite, achieving a discharge capacity of 292 mA h g −1 at the 100 th cycle. In the second approach, sucrose impregnation followed by a dehydration step within a strong acid medium was used as a carbon source, and the discharge capacity of this material was 220 mA h g −1 at the 100 th cycle. Complete electrochemical performance of all three materials was studied and compared. This study shows that the addition of carbon to Al 2 W 3 O 12 is a promising approach to enhance charge storage capacity and electrochemical performance of open-framework A 2 M 3 O 12 -based phases.