npj：鋰離子電池（LIB）陽極固體電解質介面——想要類比？

可再充式鋰離子電池（LIB）給我們的工作和生活掀起了巨大的波瀾， 推動了小型電子產品、航空領域電器的變革：因其更高的能量密度而逐漸取代了傳統的鹼性電池、鎳鎘電池和鉛酸電池等。 自1991年索尼公司首次將LIB商業化以來， 僅二十多年的時間， 鋰離子電池的能量密度逐年增加（~5 Wh/kg /Year）， 現在已達160 Wh/kg， 但仍不能滿足汽車電氣化的要求（500 - 700 Wh/kg）。 固體電解質介面（SEI）是由電解質的分解產物在電極表面上形成的鈍化層， 允許Li +傳輸但阻擋電子通過， 可防止電解質進一步分解， 確保電化學反應能夠持續。 該領域有可能成為LIB的下一個技術突破點。

由於SEI納米膜結構複雜， 加之可靠的原位實驗技術缺乏， 其形成和生長機理均未完全明瞭。 計算方法方面的重大進展使SEI形成機制的預測性模擬成為可能。 來自上海大學的施思齊教授和美國密西根州立大學的齊月教授， 綜述了SEI計算模擬領域的最新研究進展， 涉及電子結構計算到介觀尺度模型， 涵蓋電解質還原反應的熱力學和動力學、SEI形成、通過電解質設計來改性、SEI特性與電池性能間的關聯， 以及人工SEI的設計；總結了多尺度模擬， 比較了模擬結果與實驗結果；討論了SEI基本性質的計算細節， 如：電子隧道效應、鋰離子傳輸、塊體SEI和電極/(SEI/)電解質介面的化學/機械穩定性等。 綜述最後展望了計算方法在SEI性質解析和人工SEI設計中的應用前景， 並相信計算模擬與實驗相結合可以相互補充， 從而更好地瞭解SEI的複雜特性， 以利將來開發出更高效的電池。

Review on modeling of the anode solid electrolyte interphase (SEI) for lithium-ion batteries

Aiping Wang, Sanket Kadam, Hong Li,

Siqi Shi & Yue Qi

A passivation layer called the solid electrolyte interphase (SEI) is formed on electrode surfaces from decomposition products of electrolytes. The SEI allows Li+ transport and blocks electrons in order to prevent further electrolyte decomposition and ensure continued electrochemical reactions. The formation and growth mechanism of the nanometer thick SEI films are yet to be completely understood owing to their complex structure and lack of reliable in situ experimental techniques. Significant advances in computational methods have made it possible to predictively model the fundamentals of SEI. This review aims to give an overview of state-of-the-art modeling progress in the investigation of SEI films on the anodes, ranging from electronic structure calculations to mesoscale modeling, covering the thermodynamics and kinetics of electrolyte reduction reactions, SEI formation, modification through electrolyte design, correlation of SEI properties with battery performance, and the artificial SEI design. Multi-scale simulations have been summarized and compared with each other as well as with experiments. Computational details of the fundamental properties of SEI, such as electron tunneling, Li-ion transport, chemical /mechanical stability of the bulk SEI and electrode/(SEI/) electrolyte interfaces have been discussed. This review shows the potential of computational approaches in the deconvolution of SEI properties and design of artificial SEI. We believe that computational modeling can be integrated with experiments to complement each other and lead to a better understanding of the complex SEI for the development of a highly efficient battery in the future.