The use of Li metal anode in rechargeable batteries such as Li-S and Li-air is challenging due to the uncontrolled formation of lithium dendrites during repeated charge/discharge cycling, which induces various issues such as cell short circuit, aggravated adverse reactions, dead Li formation, polarization increase and large volume changes, resulting in safety concerns and low coulombic efficiencies [1]. Different characterization techniques have been used to study Li metal electrode morphological changes associated with Li dendrite formation such as scanning electron microscopy, transmission electron microscopy, atomic force microscopy and optical microscopy [2]. A large part of these characterizations were performed ex situ or in situ but under static conditions (no cycling) or operando using open cell requiring none volatile electrolyte, giving limited information on the Li growth dynamics in real systems. Recently, operando synchrotron X-ray tomography has been used to visualize the morphological evolution of Li metal electrodes in various cell configurations (e.g. Li-S cell [3]). However, the limited access to beamtime at synchrotron X-ray sources and challenges with data processing (image segmentation, volume reconstruction, artefact minimization, etc.) are major drawbacks.In the present study, a simple and low-cost method is used to monitor the electrode thickness variation associated with the Li plating/stripping process. This technique, named ‘’electrochemical dilatometry’’, consists in integrating a gap sensor or a displacement transducer within the electrochemical cell for measuring the vertical displacement of the working electrode during its cycling. It has been successfully applied for studying the volume expansion/contraction of Si-based electrodes for Li-ion batteries [4]. To the best of our knowledge, electrochemical dilatometry has never been applied to the study of Li metal electrodes. In the present study, this technique is used for studying the expansion/contraction behavior of electrodes integrating commercial porous C papers as 3D matrices for Li electrodeposition and compared to what is observed on a 2D Cu foil substrate (Figure 1).