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chem 5 seeds

Yue Liu, a Bin Li, alt=”ORCID logo” /> * a Jianhua Liu, a Songmei Li alt=”ORCID logo” /> * a and Shubin Yang a

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Pre-planted nucleation seeds for rechargeable metallic lithium anodes†

a Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Materials Science & Engineering, Beihang University, Beijing, China
E-mail: [email protected], [email protected]

Metallic lithium is one of the most favorable anode materials for next-generation energy storage systems owing to its high theoretical capacity, low density and lowest negative electrochemical potential. Despite these attractive advantages, problems induced by uneven Li deposition and volume expansion have hindered the practical application of Li-metal anodes. Among numerous efforts to stabilize metallic lithium anodes, regulating lithium deposition at the nucleation stage is challenging. Herein, we propose a strategy of pre-planting nucleation seeds to inhibit the uneven dendrite growth of metallic lithium. The nucleation and growth of lithium dendrites can be efficiently regulated by adequate heterogeneous nucleation seeds while the lamellar structure can accommodate the volume change to some extent. Benefiting from these two aspects, the Li–Cu hybrid exhibits superior electrochemical performance in terms of lower over-potential, superior cycle stability with a flatter voltage plateau and prolonged lifespan, and a high specific capacity of 2023 mA h g −1 . On this basis, electrochemical tests on full-cells with LiFePO4 as the cathode also confirm the effectiveness of the Li–Cu hybrid anode which shows highly stable cycling performance and excellent capacity retention.

Journal of Materials Chemistry A

Seeds of different cultivars of Glycine max (L.) Merr. (soybean) have strikingly different rates of water imbibition. Seeds that readily imbibe water are termed ‘soft’, while those that remain non-permeable, even after several days in water, are referred to as ‘hard’, ‘stone’, or ‘impermeable’ seeds. What prevents soybean hard seeds from taking up water? Previous work established that the initial imbibition of soft soybean seeds correlates with the presence of small cracks in the outermost cuticle that covers the seed coat, prompting a detailed analysis of soybean seed coat cutin. In this paper, it is shown that the outermost cuticle of the seed coat has an unusual chemical composition, lacking typical mid-chain-hydroxylated fatty acids but being relatively rich in other types of hydroxylated fatty acids. The cuticle of the impermeable cultivar studied contained a disproportionately high amount of hydroxylated fatty acids relative to that of the permeable ones. Moreover, a brief treatment with hot alkali released the omega-hydroxy fatty acid component of the outermost cuticle and created holes in it that caused the seeds to become permeable. This demonstrates that the outermost cuticle of the seed is the critical structure that prevents water uptake by hard seeds.