| Abstract | Lithium metal rechargeable batteries have great potential for higher energy density storage systems. Current configurations of all solid-state and anode-free cells depend on significant internal mechanical pressure (typically 0.5–1 MPa) to reduce interfacial resistance and suppress lithium dendrite formation. Mechanical stack pressure can increase over time and with use as cell components degrade. Lithium is soft at room temperature and may not be physically strong enough to support the required stack pressures in standard lithium-ion operating conditions. Compressive creep deformation of low aspect ratio lithium metal foils was measured in hermetically sealed, rigid but flexible cells at temperatures between 30–60°C and applied pressures between 0.6–3.6 MPa. Creep rates were typically on the order of a few µ m h⁻¹, depending on pressure, temperature, lithium thickness, and grain size. While difficult to notice during fast cycling these creep rates could have a pronounced effect during storage or practical use. Results suggest that pure lithium may not be strong enough for use in high energy density all solid-state devices, and that alternatives (e.g.lithium-rich alloys) should be considered. |
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