Optimising formation protocols for anode-less lithium metal batteries

Anode-less lithium metal batteries are one of the most promising technologies to improve both the energy density and manufacturing costs of lithium-ion batteries. In these cells, lithium that is stored in the cathode is deposited as metallic lithium on a thin copper current collector during charging instead of being intercalated in a graphite anode.

Members of the Degradation Project under the lead of Professor Michael De Volder at the University of Cambridge, with support from colleagues at the Universities of Oxford, Newcastle, and Sungkyunkwan (South Korea), have found that the initial lithium plating and stripping cycles during formation play a critical role in shaping the morphology of subsequent lithium deposition. This morphology has a long-term impact on cycling performance, underscoring the need for dedicated formation strategies for anode-less batteries.

Formation protocols for anode-less systems are often simply adopted from procedures optimised for graphite anodes. However, contrary to conventional approaches that favour slow formation cycles to protect graphite anodes, this new study shows that anode-less cells benefit from being formed at the highest possible current density that does not induce dendrite growth. This counterintuitive strategy was validated across three different electrolyte families, suggesting that the findings are robust and widely applicable. These insights support the adoption of new formation protocols as a universal and straightforward strategy to enhance the lifetime of anode-less lithium-ion batteries.

Image: A cross-section SEM images of lithium plated in anode-less batteries when the cell is formed slowly (C/20, left), at optimal rate (C/2, middle) and quickly (1C, right).

Case study published December 2025.