Potential-Driven Selective Na Metal Deposition-Enabled Interphase with High Lithium Dendrite Suppression Capability
Hongli Wan, Chi Chen, Ni Zhang, Shiqiang Huang, Xiayin Yao
Abstract
High Resolution Image Download MS PowerPoint Slide Voids formation during Li stripping and Li dendrite growth during Li plating are critical challenges that restrict the practical application of all-solid-state Li–metal batteries (ASSLBs). Extensive research efforts typically address these issues in isolation, thereby limiting the ability of ASSLBs to achieve a stable cyclic performance under low stack pressure. Herein, we address these two challenges simultaneously by using hard carbon-Sn (HC–Sn) as an interlayer and LiNa as an anode. After Li plating/stripping cycles, the Li 6 PS 5 Cl/HC-Sn/LiNa in situ transfers to the Li 6 PS 5 Cl/[HC-Li x Sn]Na/Na/LiNa structure, where [HC-Li x Sn]Na represents HC-Li x Sn embedded within the sodium metal. The fast Li + diffusivity of HC-Li x Sn promotes uniform Li deposition at the [HC-Li x Sn]Na/Na interface, while the soft Na in the HC-Li x Sn layer and at the [HC-Li x Sn]Na/LiNa interface suppresses void formation during Li stripping, thus, high lithium dendrite suppression capability is achieved in Li 6 PS 5 Cl/HC-Sn/LiNa. As a result, the LiNa/HC-Sn/Li 6 PS 5 Cl/HC-Sn/LiNa symmetric cell shows stable Li plating/stripping cycles of 1184 h at 1.0 mA cm –2 /4.0 mAh cm –2 under a low stack pressure of 2.0 MPa. The Co 0.1 Fe 0.9 S 2 /Li 6 PS 5 Cl/HC-Sn/LiNa cell shows high cycling stability with a capacity retention of 90.0% after 1000 cycles at an areal capacity of ∼1.5 mAh cm –2 and a high reversible capacity of 3.14 mAh cm –2 after 300 cycles at an areal capacity of ∼4.0 mAh cm –2 under the same low stack pressure of 2.0 MPa. This work provides a strategy to design ASSLSBs with a long cycle life at low stack pressure for practical application.