image: On the top, three different methods tried to synthesize dilithium hydroquinone and the corresponding characteristics are shown. On the bottom is the synthesis mechanism of obtaining pure dilithium hydroquinone by using insufficient lithium hydroxide to react with hydroquinone, and then annealing.
Credit: ©Science China Press
This study is led by Prof. Jun Chen (College of Chemistry, Nankai University). As we know, lithium-ion batteries have dominated the market of portable electronics and shown great promise for large-scale energy storage applications since their first commercialization in the early 1990s. The current electrochemistry of cathode materials in commercial lithium-ion batteries is based on lithium-ion interaction/de-interaction in transition-metal oxides or phosphates. The limitations of inorganic cathode materials mainly include scarce natural resources, recyclability issues, and high CO2 emission and energy consumption during the material production process. Thus, new cathode materials are urgent to be developed.
In recent years, organic electrode materials have attracted extensive attention because of their high abundance, environmental friendliness, and renewability. Unfortunately, the reported organic cathode materials are mostly free of lithium initially and used at oxidation states, which have to match with lithium-containing anodes such as lithium metal. The immaturity of lithium-containing anodes inevitably hinders the practical applications of most organic cathode materials. Thus, developing lithiated organic cathode materials at reduced states as lithium reservoirs to match with commercial lithium-free anode materials, such as graphite, is very meaningful for future commercial applications. However, the strict synthesis conditions derived from the use of lithium hydride or lithium methoxide and the limited reversible capacity are the two common challenges facing lithiated organic cathode materials.
To solve these problems, the team proposed a facile thermal intermolecular rearrangement method without organic solvents to synthesize lithiated organic cathode material dilithium hydroquinone, which shows a good promise as high-capacity cathodes for lithium-ion batteries. Operando characterizations uncover the reversible conversion between pristine dilithium hydroquinone with orthorhombic structure and 1,4-benzoquinone with monoclinic structure during charge and discharge processes. Furthermore, the team found that there are unique lithium−oxygen channels for facile lithium ion diffusion in dilithium hydroquinone, and the cycle life of dilithium hydroquinone can be improved by separator optimization owing to the mitigated dissolution issue. This work paves the way to promote the facile synthesis and battery applications of high-capacity lithiated organic cathode materials.
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See the article:
High-capacity dilithium hydroquinone cathode material for lithium-ion batteries
https://doi.org/10.1093/nsr/nwae146
Journal
National Science Review