Xie Jian, Chen Wangqiao, Wang Zilong, Jie Kenneth Choo Wei, Liu Ming, Zhang Qichun
School of Materials Science and Engineering, Nanyang Technological University (Singapore), 639798, Singapore, Singapore.
Temasek Laboratories @NTU, Nanyang Technological University (Singapore), Research Techno Plaza, 50 Nanyang Drive, 637553, Singapore, Singapore.
Chem Asian J. 2017 Apr 18;12(8):868-876. doi: 10.1002/asia.201700070. Epub 2017 Mar 23.
Compared to anode materials in Li-ion batteries, the research on cathode materials is far behind, and their capacities are much smaller. Thus, in order to address these issues, we believe that organic conjugated materials could be a solution. In this study, we synthesized two non-polymeric dianhydrides with large aromatic structures: NDA-4N (naphthalenetetracarboxylic dianhydride with four nitrogen atoms) and PDA-4N (perylenetetracarboxylic dianhydride with four nitrogen atoms). Their electrochemical properties have been investigated between 2.0 and 3.9 V (vs. Li /Li). Benefiting from multi-electron reactions, NDA-4N and PDA-4N could reversibly achieve 79.7 % and 92.3 %, respectively, of their theoretical capacity. Further cycling reveals that the organic compound with a relatively larger aromatic building block could achieve a better stability, as an obvious 36.5 % improvement of the capacity retention was obtained when the backbone was switched from naphthalene to perylene. This study proposes an opportunity to attain promising small-molecule-based cathode materials through tailoring organic structures.
与锂离子电池的负极材料相比，正极材料的研究相对滞后，且其容量要小得多。因此，为了解决这些问题，我们认为有机共轭材料可能是一种解决方案。在本研究中，我们合成了两种具有大芳香结构的非聚合二酐：NDA-4N（含四个氮原子的萘四甲酸二酐）和PDA-4N（含四个氮原子的苝四甲酸二酐）。研究了它们在2.0至3.9 V（相对于Li/Li）之间的电化学性质。受益于多电子反应，NDA-4N和PDA-4N分别可逆地达到其理论容量的79.7%和92.3%。进一步的循环表明，具有相对较大芳香结构单元的有机化合物可实现更好的稳定性，因为当主链从萘切换到苝时，容量保持率有明显36.5%的提高。本研究提出了一个通过定制有机结构来获得有前景的小分子正极材料的机会。
