Di Shuanlong, Li Hongguan, Zhai Boyin, Zhi Xiaojuan, Niu Ping, Wang Shulan, Li Li
Department of Chemistry, College of Science, Northeastern University, Shenyang 110819, Liaoning, P. R. China.
State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, Liaoning, P. R. China.
Proc Natl Acad Sci U S A. 2023 Aug 15;120(33):e2302375120. doi: 10.1073/pnas.2302375120. Epub 2023 Aug 7.
Lithium metal anodes with ultrahigh theoretical capacities are very attractive for assembling high-performance batteries. However, uncontrolled Li dendrite growth strongly retards their practical applications. Different from conventional separator modification strategies that are always focused on functional group tuning or mechanical barrier construction, herein, we propose a crystallinity engineering-related tactic by using the highly crystalline carbon nitride as the separator interlayer to suppress dendrite growth. Interestingly, the presence of Cl intercalation and high-content pyrrolic-N from molten salt treatment along with highly crystalline structure enhanced the interactions of carbon nitride with Li and homogenized lithium flux for uniform deposition, as supported by both experimental and theoretical evidences. The Li-Li cell with the modified separator therefore delivered ultrahigh stability even after 3,000 h with dendrite-free cycled electrodes. Meanwhile, the assembled Li-LiFePO full-cell also presented high-capacity retention. This work opens up opportunities for design of functional separators through crystallinity engineering and broadens the use of CN for advanced batteries.
具有超高理论容量的锂金属阳极对于组装高性能电池极具吸引力。然而，不受控制的锂枝晶生长严重阻碍了它们的实际应用。与传统的总是专注于官能团调节或机械屏障构建的隔膜改性策略不同，在此，我们提出了一种与结晶度工程相关的策略，即使用高度结晶的氮化碳作为隔膜中间层来抑制枝晶生长。有趣的是，实验和理论证据均支持，通过熔盐处理引入的Cl插层和高含量吡咯氮以及高度结晶的结构增强了氮化碳与锂的相互作用，并使锂通量均匀化以实现均匀沉积。因此，具有改性隔膜的锂-锂电池即使在3000小时后，电极无枝晶循环仍具有超高稳定性。同时，组装的锂-磷酸铁锂全电池也表现出高容量保持率。这项工作通过结晶度工程为功能隔膜的设计开辟了机会，并拓宽了氮化碳在先进电池中的应用。
