新型醌类聚合物合成与在高能量密度锂电池应用

Organic carbonyl electrode materials are considered as one of the most promising energy storage materials for the next generation batteries, due to their abundant resources, designable molecular structure, environment friendliness, and low cost. However, organic anode materials are faced the main issue: the average working potential of carbonyls is between 2.2 and 2.7 V which are relatively low compared with inorganic compounds, it is very hard for them to reach higher potentials(>3.0V), thus limiting their energy density. Here，we introduce electron withdrawing groups into the organic carbonyl electrode molecules to increase the working potential of carbonyls, then the organic carbonyl electrode molecules are transformed into polymers which have high working potentials and high specific capacities. And then, the study of electrochemical performance of the polyquinones is performed to examine the charge/discharge mechanism employing in situ IR, in situ XRD and solid state NMR techniques, and reveal the relationship between working potential of carbonyls and electron withdrawing groups.

有机羰基电极材料是一类来源广泛、结构可设计性强、环境友好、价格低廉的新型电池材料，是下一代可持续发展电池的理想选择之一。然而，有机羰基电极材料面临的主要问题：与无机正极材料相比，电压一般都会在2.2-2.7V（vsLi+/Li）之间，很难将它的电压提高到3.0V以上，导致了电极材料的能量密度相对较低。本项目拟通过合理的分子设计，将拉电子的基团引入醌类小分子中，并将醌类小分子聚合生成正极材料，期望通过引入吸电子基团来提高工作电压，得到高电压、高容量的有机正极材料，并进一步将羰基聚合物正极材料应用到锂离子电池中，对电池进行多循环充放电测试，探究电极材料的电化学性能。同时将采用原位红外、原位XRD、固态核磁等手段对有机正极材料的充放电机理进行探究，揭露拉电子基团与醌类正极材料工作电压的关联。

全羰基化合物（CnOn, n=3, 4, 5, 6...）是一系列只由羰基形成的化合物，分子中强吸电子的碳原子的存在使得它们对水极度不稳定，导致它们的合成有很大的挑战性。在这里，我们发明了一种简单的氧化-脱水的方法成功合成了C4O4和C5O5。我们利用核磁共振谱（碳谱、氢谱）、质谱和红外光谱证明了C4O4和C5O5的化学结构。我们选用C5O5作为正极材料组装电池，它的放电比容量为698 mAh g–1（对应的能量密度为1256 Wh kg–1）。并且，我们进一步利用非原位的红外光谱和密度泛函理论计算证明了在充放电过程中活性基团为羰基。该部分工作为全羰基化合物的合成铺平了道路，并证明了全羰基化合物是在锂离子电池中有应用前景的一类材料。