Guo Meichen, Tang Wu, Tang Chenbin, He Xuesong, Hu Jiahui, Fan Cong
School of Materials and Energy, University of Electronic Science and Technology of China (UESTC), Chengdu, 611731, P. R. China.
Key Laboratory of Advanced Energy Materials Chemistry, Ministry of Education), Nankai University, Tianjin, 300071, P. R. China.
ChemSusChem. 2023 Aug 7;16(15):e202300343. doi: 10.1002/cssc.202300343. Epub 2023 Jun 20.
Small-molecule organic cathodes face dissolution in potassium-ion batteries (PIBs). For the first time, an interesting and effective strategy is unveiled to resolve this issue by designing a new soluble small-molecule organic compound namely [N,N'-bis(2-anthraquinone)]-1,4,5,8-naphthalenetetracarboxdiimide (NTCDI-DAQ, 237 mAh g ): Through the precise manipulation of carbonization temperature and time, the molecules on the surface of NTCDI-DAQ particles can be transformed into amorphous carbon with controllable thickness. This strategy called surface self-carbonization can form a carbon protective layer on organic cathodes and significantly increase their insolubility against liquid electrolytes without affecting the electrochemical behavior of bulk particles. As a result, the as-obtained NTCDI-DAQ@C sample displays significantly improved cathode performance in PIBs. In half cells, NTCDI-DAQ@C shows superior capacity stability of 84 % compared to 35 % of NTCDI-DAQ during 30 cycles under the same conditions. In full cells with a KC anode, NTCDI-DAQ@C delivers a peak discharge capacity of 236 mAh g cathode and a high energy density of 255 Wh kg cathode in 0.1-2.8 V, with 40 % capacity retention during 3000 cycles at 1 A g . To the best of our knowledge, the integrated performance of NTCDI-DAQ@C is among the best of soluble organic cathodes reported in PIBs.
小分子有机阴极在钾离子电池（PIB）中面临溶解问题。首次揭示了一种有趣且有效的策略来解决这一问题，即设计一种新的可溶性小分子有机化合物，即[N,N'-双(2-蒽醌)]-1,4,5,8-萘四羧酸二亚胺（NTCDI-DAQ，237 mAh g）：通过精确控制碳化温度和时间，NTCDI-DAQ颗粒表面的分子可以转化为厚度可控的无定形碳。这种称为表面自碳化的策略可以在有机阴极上形成碳保护层，并显著提高其对液体电解质的不溶性，而不会影响本体颗粒的电化学行为。结果，所获得的NTCDI-DAQ@C样品在PIB中显示出显著改善的阴极性能。在半电池中，在相同条件下，NTCDI-DAQ@C在30次循环中显示出84%的优异容量稳定性，而NTCDI-DAQ为35%。在具有KC阳极的全电池中，NTCDI-DAQ@C在0.1-2.8 V范围内提供236 mAh g阴极的峰值放电容量和255 Wh kg阴极的高能量密度，在1 A g下3000次循环中容量保持率为40%。据我们所知，NTCDI-DAQ@C的综合性能在PIB中报道的可溶性有机阴极中名列前茅。
