<p>Liquid metal batteries (LMBs) based on liquid metal electrodes and molten salt electrolytes, are deemed as one of the most promising technologies for large-scale energy storage, due to the advantages of long-lifespan, low-cost and high-safety. Nevertheless, the issue of inadequate wettability between the collectors and the liquid electrodes in LMBs hinders the electrode reaction kinetics, resulting in a considerable polarisation voltage and, consequently, a reduction in the voltage efficiency of the cell. This work proposes a novel strategy for the construction of a self-generated Cr-C transition layer at the graphite collector/electrode interface, utilising Cr as a cathode additive with the objective of enhancing interfacial wettability. It was demonstrated that the formation of a Cr-C transition layer resulted in an increase in the contact area at the collector/cathode interface, as well as the reaction area at the electrolyte/cathode interface. This led to an acceleration in the kinetics of the electrode reaction. As a consequence, the voltage efficiency of Li||Sb-Sn cells was enhanced from 86.10% to 89.91%. In particular, the improvement in energy efficiency is more pronounced with an increase in the charge/discharge rate, and a reasonable proportion of chromium addition does not have a detrimental impact on battery performance.</p> Graphical Abstract <p></p>