Anode

Anode Free Anode

Anode Free

Alloy interfacial layers are confirmed as necessary to improve coulombic efficiency Researchers at the Georgia Institute of Technology and Purdue University have studied the evolution during cell cycling of 100-nm silver and gold interface layers between the Cu current collector and sulfide-based solid electrolyte in an “anode-free” configuration. The Ag and Au alloy layers form alloys with Li during plating (cell charging). This allows for uniform Li growth across the current collector, improving the coulombic efficiency and resistance to short circuiting of the cell, even though the alloys form solute regions or particulates that detach from the current collector during plating. A key feature of both the Au and Ag interlayers is that, despite morphological evolution, they remain relatively uniformly dispersed after Li deposition (either as particles for Li-Au or dissolved for Li-Ag). Therefore, at the end of stripping (discharging), the alloys return to the interface and mitigate contact loss between the Cu current collector and the solid electrolyte, avoiding a critical vulnerability of anode-free solid-state cells. Other alloys with different reaction behavior, electrode potential, and/or mechanical properties may not be as effective as the costly Ag and Au metals. A thorough morphological and electrochemical characterization helps to understand the already-known beneficial effect of Ag and Au anode interfacial layers in improving the cycling behavior of solid-state cells.

Academia | P. 215 Source: S. E. Sandoval, J. A. Lewis, P. P. Mukherjee, M. T. McDowell, et al.

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