郑州大学郭玮团队报道了从无机到有机碘——I⁺稳定实现高能锂碘电池。相关研究成果发表在2024年4月10日出版的《美国化学会杂志》。

有机材料因其在制备和来源方面的可持续性，而被认为是一类有前途的金属离子电池阴极。然而，具有高能量密度和应用潜力的有机电池需要高放电电压、多电子转移和长循环性能。

该文中，研究人员报道了一种特殊的锂-碘（Li//I₂）电池，其中由氢碘酸（HI）和4，4′-联吡啶（BPD）之间的路易斯酸碱配位形成的有机碘（BPD-HI）阴极，能够通过I^–/I⁰和I⁰/I⁺氧化还原对进行2e^–转移。由BPD稳定的I⁺在～3.4 V时表现出高放电电压平台。

值得注意的是，从无机碘到有机碘，它实现了所实现容量的2倍增加，高达～400 mA h gI^–1（基于BPD-HI的质量，理论值为422 mA h gI^–1和245.6 mA h g^–1），并且能量密度超过2倍，达到1160 W h kgI^–1（理论值为1324 W h kgI^–1）。更重要的是，在2A gI^–1的电流密度下，Li//BPD-HI电池在850次循环中的容量保持率达到85%。

这种简单的策略使带正电荷的I⁺在可充电锂电池中具有电化学活性。新发现的氧化还原化学为开发高能量密度的有机电池提供了新的见解。

附：英文原文

Title: From Inorganic to Organic Iodine: Stabilization of I+ Enabling High-Energy Lithium–Iodine Battery

Author: Fulong Zhu, Ziqiu Li, Zhongju Wang, Yongzhu Fu, Wei Guo

Issue&Volume: April 10, 2024

Abstract: Organic materials have been considered a class of promising cathodes for metal-ion batteries because of their sustainability in preparation and source. However, organic batteries with high energy density and application potential require high discharge voltage, multielectron transfer, and long cycling performance. Here, we report an exceptional lithium–iodine (Li//I2) battery, in which the organic iodine (BPD-HI) cathode formed by the Lewis acid–base coordination between hydroiodic acid (HI) and 4,4′-bipyridine (BPD) allows 2e– transfer via the I–/I0 and I0/I+ redox couples. The I+ stabilized by BPD exhibits a high discharge voltage plateau at ～3.4 V. Remarkably, from inorganic to organic iodine, it realizes a 2-fold increase in the achieved capacity, up to ～400 mA h gI–1 (Theor. 422 mA h gI–1 and 245.6 mA h g–1 based on the mass of BPD-HI), and an over 2-fold energy density, reaching 1160 W h kgI–1 (Theor. 1324 W h kgI–1). More importantly, a capacity retention rate of 85% over 850 cycles is attained for the Li//BPD-HI battery at a current density of 2 A gI–1. This facile strategy enables positively charged I+ to be electrochemically active in a rechargeable lithium battery. The new redox chemistry discovered provides new insights for developing organic batteries with high energy density.

DOI: 10.1021/jacs.3c14619

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c14619