Stable metal anodes enabled by a labile organic molecule bonded to a reduced graphene oxide aerogel
Stable metal anodes enabled by a labile organic molecule bonded to a reduced graphene oxide aerogel
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DOI：
10.1073/pnas.2001837117
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发表时间：
2020-11
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通讯作者：
Yue Gao;Daiwei Wang;Y. Shin;Zhifei Yan;Z. Han;Ke Wang;M. Hossain;Shuling Shen;Atif AlZahrani;A. V. van Duin;T. Mallouk;Donghai Wang
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作者：
Yue Gao;Daiwei Wang;Y. Shin;Zhifei Yan;Z. Han;Ke Wang;M. Hossain;Shuling Shen;Atif AlZahrani;A. V. van Duin;T. Mallouk;Donghai Wang
基于金属阳极的可充电电池由于其高能量密度而非常受欢迎。然而，电化学界面通常不利于金属沉积，导致枝晶金属生长和不稳定的固-电解质界面相（SEI）。我们用一种不稳定的有机分子，苯磺酰氟改变了界面。该分子结合到还原氧化石墨烯气凝胶的表面，不仅可以引导均匀的金属沉积，还可以形成稳定的SEI层。锂金属电池具有稳定的循环性能和良好的低温耐受性。稳定的钠和锌阳极也被实现，证明了这一概念的多功能性。金属阳极（锂、钠和锌）在可充电电池技术中很有吸引力，但由于不利的金属-电解质界面导致不均匀的金属沉积和不稳定的固体-电解质界面（SEI）而受到困扰。在这里，我们报道了使用电化学不稳定的分子来调节电化学界面，引导均匀的锂沉积和稳定的SEI。分子，苯磺酰氟，被结合到还原氧化石墨烯气凝胶的表面。在金属沉积过程中，这种不稳定的分子不仅产生金属配位苯磺酸盐阴离子，引导金属均匀沉积，而且为SEI提供氟化锂，改善锂表面钝化。因此，在6.0 mA cm−2的高电流密度下，实现了低成核过电位的高效锂沉积。经过400次循环后，Li|LiCoO2电池的容量保持率为85.3%，并且该电池还能耐受低温（- 10°C）操作，没有额外的容量衰减。这一策略也适用于钠阳极和锌阳极。
Significance Rechargeable batteries based on metal anodes are highly desirable due to their high energy density. However, the electrochemical interface is generally not favorable for metal deposition, resulting in dendritic metal growth and an unstable solid–electrolyte interphase (SEI). We altered the interface using a labile organic molecule, benzenesulfonyl fluoride. This molecule was bonded to the surface of a reduced graphene oxide aerogel, which not only guides uniform metal deposition but also enables formation of a stable SEI layer. The lithium metal batteries showed stable cycling and excellent tolerance to low-temperature operation. Stable sodium and zinc anodes were also realized, demonstrating the versatility of this concept. Metallic anodes (lithium, sodium, and zinc) are attractive for rechargeable battery technologies but are plagued by an unfavorable metal–electrolyte interface that leads to nonuniform metal deposition and an unstable solid–electrolyte interphase (SEI). Here we report the use of electrochemically labile molecules to regulate the electrochemical interface and guide even lithium deposition and a stable SEI. The molecule, benzenesulfonyl fluoride, was bonded to the surface of a reduced graphene oxide aerogel. During metal deposition, this labile molecule not only generates a metal-coordinating benzenesulfonate anion that guides homogeneous metal deposition but also contributes lithium fluoride to the SEI to improve Li surface passivation. Consequently, high-efficiency lithium deposition with a low nucleation overpotential was achieved at a high current density of 6.0 mA cm−2. A Li|LiCoO2 cell had a capacity retention of 85.3% after 400 cycles, and the cell also tolerated low-temperature (−10 °C) operation without additional capacity fading. This strategy was applied to sodium and zinc anodes as well.