An oligomeric solid–electrolyte interphase (SEI) constructed by electrolyte engineering improves the cyclability of lithium (Li) metal batteries. However, to spontaneously establish a SEI with elasticity and self-healing features, as well as high ionic conductivity is still a huge challenge due to the uncontrollable SEI formation process. Herein, we first synthesize an ionic conductive elastomer (ICE) through the in situ chain scission of the polylactic acid precursor triggered by the Li metal. Firstly, different from conventional elastomers, the resulting lithiated polymer here possessed a unique Li⁺-crosslinked network with the presence of a trace amount of liquid electrolyte inside the ICE. Moreover, the cationic Li⁺ promptly generates ionic groups to establish adaptive motifs, endowing the network with remarkable dynamic reversibility and improved elasticity. Finally, the ICE offered rapid Li⁺-transport pathways through the molecular backbones and the liquid electrolyte present within the framework. As such, the SEI armed with the self-healing, elastic, and conductive ICE can effectively suppress the growth of Li dendrites and maintain the structural integrity, visually demonstrated by in situ transmission electron microscopy. Consequently, a surprising lifespan over 22 700 cycles (∼9110 h) at a current density of 5 mA cm⁻² has been achieved in symmetric cells that largely exceeds the current records, accordingly guaranteeing stable high-capacity pouch cells. This work proposes a brand-new elastomer for robust and conductive interphase design towards achieving high-energy Li or other alkali metal batteries.

中文翻译：

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自修复锂交联弹性体可促进高度坚固且导电的固体电解质界面


通过电解质工程构建的低聚固体电解质界面（SEI）可提高锂（Li）金属电池的循环性能。然而，由于SEI形成过程不可控，自发建立具有弹性、自修复特性以及高离子电导率的SEI仍然是一个巨大的挑战。在这里，我们首先通过锂金属引发的聚乳酸前体的原位断链合成了离子导电弹性体（ICE）。首先，与传统的弹性体不同，所得的锂化聚合物具有独特的Li ⁺ 交联网络，并且ICE内部存在微量液体电解质。此外，阳离子Li ⁺ 迅速生成离子基团以建立适应性基序，赋予网络显着的动态可逆性和改善的弹性。最后，ICE 提供了通过分子主链和框架内存在的液体电解质的快速 Li ⁺ 传输途径。因此，配备自愈、弹性和导电ICE的SEI可以有效抑制锂枝晶的生长并保持结构完整性，这一点可以通过原位透射电子显微镜直观地证明。因此，对称电池在电流密度为 5 mA cm ⁻² 下实现了超过 22 700 个循环（∼9110 h）的令人惊讶的寿命，大大超过了当前的记录，从而保证了稳定的高容量软包电池。这项工作提出了一种全新的弹性体，用于坚固且导电的界面设计，以实现高能锂或其他碱金属电池。