The Li 0-1 CuO 2 electrode is also worth highlighting. Its high theoretical capacity of 261 mA h g -1 scores it at the 93rd percentile by specific capacity among the filtered electrodes, and it operates at a flat 4.58 V. It can be speculated that this material's frequent appearance in the top cells could be due to the fact that the space investigated requires it to be coupled with electrodes operating close to 3 -3.5 V. As we pointed out above, the recent research on battery materials is probably biased towards high energy materials, hence it could be that the materials present in the MP database operating at 3 -3.5 V tend to also have higher theoretical capacity than the electrodes operating at lower voltages. This is consistent with what can be observed in Figure . The Figure displays a kernel density estimation of the bivariate distribution of the MP electrodes versus two variables: their theoretical specific capacity and the average operational voltage. First of all, it is interesting to visualize how skewed the distribution is towards the electrodes with both high capacity and high operational voltage, leaving the high capacity, low operational voltage space largely unexplored. This could be explained by a research bias towards high energy PEAMs, that naturally fit in the high voltage, high capacity space, and it helps in rationalizing why we observe multiple appearances of the same electrodes in Figure . It becomes clear that when seeking cells with average voltage between 0.6 and 1.2 V, the two electrodes Li 0-1 CuO 2 (as PEAM), Li 0-1 TiNCl and Li 0-1 VS 2 (as NEAM) can only be matched with other AMs falling within the highlighted regions. Such a region for the former material contains more AMs with high specific capacity, resulting in a higher probability of obtaining low-voltage cells with high capacity. This, in turn, results in having multiple highest-capacity cells containing this very electrode. The low-voltage cells obtained with Li 0-1 CuO 2 would also naturally operate at high extreme voltages, being both Li 0-1 CuO 2 and its low-voltage counter NEAMs operational around 4 V.