<p>Organic electrode materials with bipolar-redox activity are a promising candidate for high-energy aluminum-ion batteries (AIBs), but face the capacity ceiling due to limited active sites and low electron transfer number. To universally address this issue, seeking for a kind of multisite bipolar organic material to achieve multielectron transfer is a prerequisite but challenging. Herein, we develop a 12-electron transfer tetraalkynylporphyrin macrocycle positive electrode with two p-type amine (‒NH‒) motifs, two n-type imine (C = N) motifs and four n-type alkynyl (C ≡ C) motifs. The bipolar 18π-electron porphyrin macrocycle can alternately bind and release AlCl<sub>4</sub><sup>−</sup> anions at ‒NH‒ sites and AlCl<sub>2</sub><sup>+</sup> cations at C = N sites (oxidized from 18π to 16π or reduced from 18π to 20π), achieving four electrons transfer. Furthermore, each terminal C ≡ C site can also coordinate with two AlCl<sub>2</sub><sup>+</sup> cations, thereby delivering eight electrons. The designed aluminum-organic battery achieves a high capacity of up to 347 mAh g<sup>−1</sup> (3-6 times that of conventional graphite positive electrode, 60-120 mAh g<sup>−1</sup>) and a high specific energy of 312 Wh kg<sup>−1</sup> (up to 150% compared to cells with graphite as positive electrode) based on the mass of positive electrode materials.</p>

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A bipolar-redox tetraalkynylporphyrin macrocycle positive electrode with 12-electrons-transfer for high-energy aluminum-organic batteries

  • Yuxi Guo,
  • Wei Wang,
  • Ke Guo,
  • Xiaodong Chen,
  • Mingyong Wang,
  • Zheng Huang,
  • Yanli Zhu,
  • Weili Song,
  • Shuqiang Jiao

摘要

Organic electrode materials with bipolar-redox activity are a promising candidate for high-energy aluminum-ion batteries (AIBs), but face the capacity ceiling due to limited active sites and low electron transfer number. To universally address this issue, seeking for a kind of multisite bipolar organic material to achieve multielectron transfer is a prerequisite but challenging. Herein, we develop a 12-electron transfer tetraalkynylporphyrin macrocycle positive electrode with two p-type amine (‒NH‒) motifs, two n-type imine (C = N) motifs and four n-type alkynyl (C ≡ C) motifs. The bipolar 18π-electron porphyrin macrocycle can alternately bind and release AlCl4 anions at ‒NH‒ sites and AlCl2+ cations at C = N sites (oxidized from 18π to 16π or reduced from 18π to 20π), achieving four electrons transfer. Furthermore, each terminal C ≡ C site can also coordinate with two AlCl2+ cations, thereby delivering eight electrons. The designed aluminum-organic battery achieves a high capacity of up to 347 mAh g−1 (3-6 times that of conventional graphite positive electrode, 60-120 mAh g−1) and a high specific energy of 312 Wh kg−1 (up to 150% compared to cells with graphite as positive electrode) based on the mass of positive electrode materials.