Stability and performance of lithium metal batteries using silicon and silver alloyed separator surfaces

Lithium metal is renowned for its exceptional theoretical capacity and the lowest electrochemical potential, making it a cornerstone for batteries that can push the boundaries of energy and power density. However, its widespread adoption has been hindered by significant drawbacks, such as an unstable solid electrolyte interface (SEI) layer, substantial volume changes during charge-discharge cycles, and the formation of lithium dendrites. In our study, we have addressed these challenges by employing an innovative alloying technique to modify the surface of the separator with silicon (Si) and silver (Ag). This approach facilitates the formation of LiSi and LiAg alloys on the separator surface, leading to the creation of a novel lithium metal-lithium alloy composite anode. Our electrochemical tests have demonstrated that batteries equipped with this surface-modified lithium alloy composite anode exhibit superior coulombic efficiency and an impressively extended cycle life. Furthermore, when utilizing an ether-based electrolyte, the LiAg and LiSi alloy composite anodes have shown remarkable capacity retention rates of 89.1 % and 86.3 %, respectively, after 200 cycles in full cell tests. These results are notably superior to those of anodes made with bare lithium metal. In conclusion, the development of the face-to-face lithium alloy composite anode holds great promise for the practical application of lithium batteries with enhanced stability and performance. This advancement is a significant step towards realizing the full potential of lithium metal batteries in a variety of applications.