Liu Mili, Jia Yunqi, Liu Jiangwen, Chen Kang, Zhong Hao, Jiang Lin, Liu Hui, Ouyang Liuzhang, Zhu Min
School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou, PR China.
School of Microelectronics, Shanghai University, Shanghai, PR China.
Nat Commun. 2025 Aug 20;16(1):7772. doi: 10.1038/s41467-025-63086-x.
The hydrolysis/methanolysis of silicon has received considerable attention to achieve efficient and on-demand hydrogen conversion. However, the intense covalent network and highly localized electrons in pure Si impede its reactivity with water (HO) or methanol (CHOH), thereby hindering the hydrogen release. In this work, we report the synthesis of Zintl phase alkalis-Si alloys via simple ball-milling or sintering, showing eminent performance in enhancement of HO/CHOH dissociation. Experiments combined with DFT calculations have revealed that the obtained Zintl phase alloys exhibit discrete Si clusters containing well-defined unpaired electrons that efficiently facilitate the interaction between reductant and solvent molecules. Such an effect thereby reduces the activation barrier of HO/CHOH dissociation to yield active intermediates containing Si-H structure, which significantly promotes the hydrogen release with favorable kinetics and efficiency. The optimal Zintl LiSi alloy achieves ultrahigh Si utilization rates of 86.9% in water and 98.1% in methanol at 25 °C, respectively. Remarkably, even at an extremely low temperature of -40 °C, a substantial hydrogen yield of 1.091 L g in methanol is retained. Furthermore, the desirable Zintl phase-water reaction inspires an economic-friendly "charge-hydrolysis-separation" strategy, for effectively recovering the valuable lithium, graphite, Si and Cu resources from the degraded lithium-ion batteries.
硅的水解/甲醇解已受到广泛关注，旨在实现高效且按需的氢转化。然而，纯硅中强烈的共价网络和高度局域化的电子阻碍了其与水（HO）或甲醇（CHOH）的反应活性，从而阻碍了氢的释放。在这项工作中，我们报道了通过简单的球磨或烧结合成Zintl相碱金属 - 硅合金，其在增强HO/CHOH离解方面表现出卓越性能。结合DFT计算的实验表明，所获得的Zintl相合金呈现出离散的硅簇，其中含有明确的未配对电子，这些电子有效地促进了还原剂与溶剂分子之间的相互作用。这种效应从而降低了HO/CHOH离解的活化能垒，以产生含有Si - H结构的活性中间体，这显著促进了具有良好动力学和效率的氢释放。最佳的Zintl LiSi合金在25°C时在水中的硅利用率高达86.9%，在甲醇中的硅利用率高达98.1%。值得注意的是，即使在-40°C的极低温度下，甲醇中的氢产量仍保持在1.091 L g。此外，理想的Zintl相 - 水反应启发了一种经济友好型的“充电 - 水解 - 分离”策略，用于从退化的锂离子电池中有效回收有价值的锂、石墨、硅和铜资源。
