Stable Anode‐Free All‐Solid‐State Lithium Battery through Tuned Metal Wetting on the Copper Current Collector

Abstract

A stable anode‐free all‐solid‐state battery (AF‐ASSB) with sulfide‐based solid‐electrolyte (SE) (argyrodite Li6PS5Cl) is achieved by tuning wetting of lithium metal on “empty” copper current‐collector. Lithiophilic 1 µm Li2Te is synthesized by exposing the collector to tellurium vapor, followed by in situ Li activation during the first charge. The Li2Te significantly reduces the electrodeposition/electrodissolution overpotentials and improves Coulombic efficiency (CE). During continuous electrodeposition experiments using half‐cells (1 mA cm−2), the accumulated thickness of electrodeposited Li on Li2Te–Cu is more than 70 µm, which is the thickness of the Li foil counter‐electrode. Full AF‐ASSB with NMC811 cathode delivers an initial CE of 83% at 0.2C, with a cycling CE above 99%. Cryogenic focused ion beam (Cryo‐FIB) sectioning demonstrates uniform electrodeposited metal microstructure, with no signs of voids or dendrites at the collector‐SE interface. Electrodissolution is uniform and complete, with Li2Te remaining structurally stable and adherent. By contrast, an unmodified Cu current‐collector promotes inhomogeneous Li electrodeposition/electrodissolution, electrochemically inactive “dead metal,” dendrites that extend into SE, and thick non‐uniform solid electrolyte interphase (SEI) interspersed with pores. Density functional theory (DFT) and mesoscale calculations provide complementary insight regarding nucleation‐growth behavior. Unlike conventional liquid‐electrolyte metal batteries, the role of current collector/support lithiophilicity has not been explored for emerging AF‐ASSBs.

Chlorine-rich lithium argyrodite enables stable interfacial Li plating/stripping behavior in anode-free all-solid-state batteries

“…This implies the synergistic effect of the combination of a chlorine-rich Li-argyrodite and a stable interlayer for AFASSBs. As a result, it achieved a steady-state cycling CE of 95% without any external pressure, which is comparable with reported values (84–92% CE under no pressure, 32 99% CE under 13 MPa, 41 99.8% under 30 MPa 31 ).…”

Intermetallics Based on Sodium Chalcogenides Promote Stable Electrodeposition–Electrodissolution of Sodium Metal Anodes

“…No characteristic peaks of elemental Te were detected, indicating complete reaction of Te with the CF. [82] Figure S6, Supporting Information, displays transmission electron microscopy (TEM) analysis obtained from an electron transparent portion of a Cu 2 Te platelet. Figure S6a,b, Supporting Information, shows bright field images of the specimen, while Figure S6c, Supporting Information, provides a high-resolution TEM (HRTEM) image with an inset showing the associated selected area electron diffraction pattern.…”

Structural and Electrochemical Evolution of Alloy Interfacial Layers in Anode-Free Solid-State Batteries

“…Interfacial materials, including Li alloys and others, have previously been investigated in anode-free and Li-excess SSBs to improve cycling. [36][37][38][39][40] Silver-carbon composite layers can facilitate uniform cyclic Li deposition/stripping. 12 Telluride layers have also been shown to promote uniform growth.…”

“…12 Telluride layers have also been shown to promote uniform growth. 38 Lithium-magnesium alloy interfaces can enhance diffusion and diminish voiding. 41 While these studies have shown improved cell performance, there is a lack of knowledge of the mechanistic influence of interfacial layers on the evolution of Li in anode-free SSBs.…”