浙江大学范修林研究组开发出表面化学配位稳定高能锂金属电池的富镍阴极。该项研究成果发表在2025年3月4日出版的《美国化学会杂志》上。

研究小组提出了一种sp²诱导机制，通过分子与阴极表面之间的界面轨道耦合来解决配位缺陷。sp²杂化高氟烯烃以不饱和键为特征，具有高度的离域电子性质（电子离域指数>0.95 au）和较高的阳极稳定性（电离电位>10 eV）。这些特性保证了与富镍阴极之间的相互作用是稳定的，有利于诱导轨道的形成。这些低能轨道可容纳Ni三维电子，有效地缓解了界面配位缺陷，抑制了表面副反应。

在sp²杂化高氟烯烃中，（全氟丁基）乙烯（PFBE）因其在阴极表面具有最强的相互作用和良好的配位互补性而被确定为最佳的诱导分子。在4.4 V Li||LiNi_0.8Mn_0.1Co_0.1O₂ （30 μm Li，高负载3.7 mAh cm^-2 NMC811）的电池中，与不含PFBE的电解质进行175次循环相比，PFBE基电解质显著缓解了阴极表面结构的退化，并表现出显著的循环稳定性，在320次循环中，容量保持率达到80%。这项工作阐明了sp²诱导钝化高催化阴极界面的机制，为耐用、高能侵略性锂金属电池铺平了道路。

研究人员表示，电极-电解质界面的稳定性是影响锂金属电池电化学性能的关键因素。然而，在贫镍富阴极表面，配位缺乏过渡金属的强催化作用显著加剧了与锂金属相容的醚基电解质的寄生反应，从而降低了高压富镍电池的循环稳定性。

附：英文原文

Title: Surface Chemical Coordination Stabilizes Ni-Rich Cathodes for High-Energy Li-Metal Batteries

Author: Jinze Wang, Shuoqing Zhang, Ruhong Li, Long Chen, Haikuo Zhang, Baochen Ma, Sen Jiang, Tao Zhou, Jiajie Huang, Haotian Zhu, Long Li, Lixin Chen, Tao Deng, Xiulin Fan

Issue&Volume: March 4, 2025

Abstract: The stability of the electrode–electrolyte interface is a critical factor influencing the electrochemical performance of Li-metal batteries. However, on the delithiated Ni-rich cathode surface, the strong catalytic effects of transition metals with coordination deficiency significantly aggravate the parasitic reactions with Li-metal-compatible ether-based electrolytes, thereby reducing the cycling stability of high-voltage Ni-rich batteries. Here, we propose an sp²-induction mechanism to address coordination deficiency through the coupling of interfacial orbitals between molecules and the cathode surface. Sp²-hybrid high-fluorinated olefins, characterized by unsaturated bonds, exhibit highly delocalized electronic properties (electron delocalization index >0.95 au) and elevated anodic stability (ionization potential >10 eV). These characters ensure robust and stable interactions with the Ni-rich cathode, facilitating the formation of induced orbitals. These low-energy orbitals accommodate Ni 3d electrons, effectively mitigating the interfacial coordination deficiency and inhibiting surface side reactions. Among the sp²-hybrid high-fluorinated olefins, (perfluorobutyl)ethylene (PFBE) is identified as an optimal inducing molecule due to its strongest interaction and excellent coordination complementarity on the cathode surface. The PFBE-based electrolyte significantly alleviates the degradation of cathode surface structure and demonstrates remarkable cyclic stability, achieving 80% capacity retention over 320 cycles for a 4.4 V Li||LiNi_0.8Mn_0.1Co_0.1O₂ (30 μm Li, high load 3.7 mAh cm^–2 NMC811) full cell, compared to 175 cycles with a PFBE-absent electrolyte. This work elucidates the sp²-induction mechanism for passivating the high-catalytic cathode interface, paving the way for durable, high-energy aggressive Li-metal batteries.

DOI: 10.1021/jacs.4c16406

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c16406