2) Surface impurities of CCs
In the case of AFLMBs, the direct deposition of Li on the surface of CCs is inevitable. However, impurities or a non-uniform native oxide layer on the surface of CCs consumes active Li and increases the Li nucleation barrier, resulting in adverse effects on the morphology of the initial and subsequent growth of Li.[69] Furthermore, the uneven surface properties of CCs can induce preferential growth of Li, causing dendrite formation. Therefore, it is important to maintain the surface of CCs by removing impurities and storing them to prevent contamination to improve the reversibility of Li.