Zhang Zibo, Wang Jian, Qin Haozhe, Zhang Bao, Lin Hongzhen, Zheng Weitao, Wang Dong, Ji Xiaobo, Ou Xing
Hunan Province Key Laboratory of Chemical Power Source, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
School of Metallurgy and Environment, Central South University, Changsha 410083, P. R. China.
ACS Nano. 2024 Jan 23;18(3):2250-2260. doi: 10.1021/acsnano.3c09849. Epub 2024 Jan 5.
Lithium metal batteries (LMBs) offer significant advantages in energy density and output voltage, but they are severely limited by uncontrollable Li dendrite formation resulting from uneven Li behaviors and high reactivity with potential co-solvent plating. Herein, to uniformly enhance the Li behaviors in desolvation and diffusion, the local Li solvation shell structure is optimized by constructing an anion-braking separator, hence dynamically reducing the self-amplifying behavior of dendrites. As a prototypal, two-dimensional lithiated-montmorillonite (LiMMT) is blade-coated on the commercial separator, where abundant -OH groups as Lewis acidic sites and electron acceptors could selectively adsorb corresponding FSI anions, regulating the solvation shell structure and restricting their migration. Meanwhile, the weakened anion mobility delays the time of breaking electrical neutrality, and the Li nucleation density is quantified through the respective experimental, theoretical and spectroscopical results, providing a comprehensive understanding of modifying anion and cation behaviors on dendritic growth suppression. As anticipated, a long Li plating/stripping lifespan up to 1800 h and a significantly increased average Coulombic efficiency of 98.8% are achieved under 3.0 mAh cm. The fabricated high-loading Li-LFP or Li-NCM523 full-cells display the cycle durability with enhanced capacity retention of nearly 100%, providing the instructive guide towards realizing dendrite-free LMBs.
锂金属电池（LMBs）在能量密度和输出电压方面具有显著优势，但由于锂行为不均匀以及与潜在的共溶剂电镀反应性高导致不可控的锂枝晶形成，使其受到严重限制。在此，为了均匀地增强锂在去溶剂化和扩散过程中的行为，通过构建阴离子制动隔膜优化局部锂溶剂化壳结构，从而动态降低枝晶的自放大行为。作为原型，二维锂化蒙脱石（LiMMT）被刮刀涂覆在商用隔膜上，其中大量作为路易斯酸性位点和电子受体的 -OH 基团可以选择性地吸附相应的 FSI 阴离子，调节溶剂化壳结构并限制它们的迁移。同时，减弱的阴离子迁移率延迟了打破电中性的时间，并且通过各自的实验、理论和光谱结果对锂成核密度进行了量化，全面了解了修饰阴离子和阳离子行为对抑制枝晶生长的影响。正如预期的那样，在 3.0 mAh cm 条件下实现了长达 1800 h 的长锂电镀/剥离寿命以及显著提高的平均库仑效率 98.8%。所制备的高负载锂 - 磷酸铁锂（Li-LFP）或锂 - 镍钴锰酸锂（Li-NCM523）全电池显示出循环耐久性，容量保持率接近 100%，为实现无枝晶锂金属电池提供了指导性方向。
