High-voltage LiCoO₂ is a promising cathode material for ultrahigh-energy lithium-ion batteries, particularly in the commercialization of 5G technology. However, achieving long-term operational stability remains a significant challenge. Herein, a quaterpolymer additive with multiple functional groups is introduced to enhance the electrochemical performance of LiCoO₂ cathode at 4.5 V. The capacity remains 96% after 100 cycles at room temperature and 94.4% after 50 cycles even at 45 °C. The sulfonate and ester groups of the quaterpolymer additive serve as lithium carriers, providing high voltage resistance and fast ionic conductivity with increased lithium-ion diffusion coefficients during the charge/discharge processes. The incorporation of a quaterpolymer additive also improves the dispersion properties and peel strength of the LiCoO₂ cathodes. The coordination between the sulfonate groups and Li⁺ as well as the amine-based derivatives and Lewis acid of PF₅ is expected to disrupt the Li⁺ solvation shell and deactivate the PF₅ reactivity, therefore suppressing electrolyte decompositions. Furthermore, the superior interactions between sulfate ester (O atoms)/amide (N atoms) groups of copolymer additive and superficial cobalt atoms of LiCoO₂ provide a compensating charge to Co, inhibiting the surface cobalt dissolution, irreversible oxygen redox reaction, and the detrimental LiCoO₂ phase transition from O3 to H1–3. The use of a tiny amount of polymer additive presents an effective approach to stabilizing high-voltage LiCoO₂, offering valuable insights for the design of high-energy battery materials.

中文翻译：

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一石多鸟：具有多功能基团的共聚物可提高钴酸锂阴极在 4.5 V 下的循环稳定性


高压 LiCoO₂ 是一种很有前途的超高能锂离子电池正极材料，特别是在 5G 技术的商业化中。然而，实现长期运营稳定性仍然是一项重大挑战。本文引入了一种具有多个官能团的四元聚合物添加剂，以增强 LiCoO₂ 阴极在 4.5 V 下的电化学性能。即使在 45 °C 下，在室温下循环 100 次后，容量仍保持 96%，在 50 次循环后容量仍保持 94.4%。 四元聚合物添加剂的磺酸盐和酯基用作锂载体，在充电/放电过程中提供高耐电压和快速离子电导率，并增加锂离子扩散系数。四元聚合物添加剂的加入还改善了 LiCoO₂ 阴极的分散性能和剥离强度。PF₅ 的磺酸盐基团和 Li⁺ 以及胺基衍生物和路易斯酸之间的配位预计将破坏 Li⁺ 溶剂化壳并使 PF₅ 反应性失活，从而抑制电解质分解。此外，共聚物添加剂的硫酸酯（O 原子）/酰胺（N 原子）基团与 LiCoO₂ 的表面钴原子之间的优越相互作用为 Co 提供了补偿电荷，抑制了表面钴溶解、不可逆的氧氧化还原反应以及有害的 LiCoO₂ 从 O3 到 H1-3 的相变。使用微量的聚合物添加剂提供了一种稳定的高压 LiCoO₂ 的有效方法，为高能电池材料的设计提供了有价值的见解。