Singapore research institute A* STAR researchers have found that adding organic materials and graphene oxide to lithium-ion batteries can reduce costs and make them more environmentally friendly.
Researchers at Singapore’s largest research institute, Science, Technology and Research (A*STAR) found that adding organic materials to lithium-ion batteries can reduce costs and make them More environmentally friendly. The team developed an organic battery positive electrode that has significantly improved electrochemical performance compared to previous organic positive electrode materials. Crucially, the new materials are also strong and stable over thousands of battery charge/discharge cycles.
The positive electrode in a lithium-ion battery is a key component. Previously they studied an electron-deficient rigid organic molecule called hexa-naphthalene (HATN) as an organic positive electrode material for lithium-ion batteries. However, its promising initial performance drops rapidly during use as the molecule begins to dissolve into the liquid electrolyte of the cell.
Now, A* Yugen Zhang and his colleagues at STAR’s Institute of Bioengineering and Nanotechnology have developed a new cathode material in which HANT is combined with graphene oxide to prevent the dissolution of organic matter.
In graphene oxide The monoatomic thick carbon atom sheet is partially covered by an oxygen atom layer. “The graphene oxide has excellent electron conductivity and surface oxygen functional groups, and can form a hydrogen bond interaction with the HATN. Zhang explained that this makes graphene oxide a promising candidate for the formation of HANT-graphene oxide nanocomposites.
The performance of nanocomposites exceeds expectations. These materials combine to form core-shell nanoparticles. Rods, in which the HANT is coated with graphene oxide. “The graphene oxide and HATN form a very good composite structure, which solves the problem of the dissolution of the HANT in the electrolyte and makes the positive electrode have very good cycle stability,” Zhang said. A lithium ion battery using this material as its positive electrode maintains 80% of its capacity after 2000 charge/discharge cycles.
When they combine graphene oxide with hexaazaphthalene naphthoic acid When the (HATNTA) HANT derivatives were combined, the team found better performance. After 2,000 charge/discharge cycles, batteries made from this material retained 86% of their capacity. Improved performance may be due to HANTTA a polar carboxylic acid group on the molecule that binds the molecule more strongly to graphene oxide.
Zhang said the team is continuing to develop new materials to improve the performance of organic cathodes. Graphene In addition to the alternatives, the team is also working on a porous polymer based on HANT as an organic positive electrode material, which enhances ion flow during battery charging and discharging.
Source: A * STAR
Links: Wang, J., Tee, K., Lee, Y., Riduan, SN and Zhang, Y. Hexaazatriphenylenederivatives/GO composites as organic cathodes for lithium ion batteries. Journal of Materials Chemistry A 6, 2752-2757(2018).