Background
The market for high energy density batteries is vast, with application ranging from consumer electronics, transportation and grid storage. There is an increasing need to develop new battery chemistry beyond Li-ion with superior performance. The design of batteries that harness multivalent ions, such as Mg2+, Zn2+, and Al3+, is a longstanding goal of battery research due to the potential higher energy density, lower cost, and greater scalability of multivalent chemistries. However, facilitating multivalent ion intercalation at the cathode with high capacity, high voltage, fast discharge rates, and with good reversibility has been a challenge. Unlike Li+, robust multivalent ion intercalation in graphite has proved unfeasible due to strong, irreversible, cation-pi interactions between the highly charged ions and the aromatic graphite sheets.
Description
Researchers at the University of Nevada, Reno have designed new batteries based on the intercalation of multivalent ions in atomically-precise nanographenes. While graphenes and nanographenes have been previously used in batteries, our nanographenes are synthesized through a bottom-up approach, via alkyne benzannulation, that enables the production of atomically-precise structures with tunable physical and chemical properties. These attributes allow us to build batteries with enhanced performance. As a proof of concept, reversible Zn2+ intercalation in peropyrene-based nanographenes has been demonstrated and batteries from the resulting materials have been built. We expect users to have batteries with about twice the volumetric energy density for Mg2+ or about three times the volumetric energy density for Al3+. Furthermore, the cycle life of these batteries should be excellent due to the similarity of nanographenes to graphite, the latter of which possesses superior cyclability compared to most other materials.
Advantages
- Allow reversible multivalent ion intercalation
- Higher volumetric energy density than traditional Li-ion batteries
- Excellent battery cyclability
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