Improved performance of lithium ion batteries by employment of electrolyte containing nanodiamonds and water

Commercial lithium ion batteries (LIBs) are usually required to avoid the presence of H2O, as the intercalation of H2O molecules would lead to the degradation of both electrolyte and graphite anode, resulting in irreversible failure of the batteries. In this work, we demonstrate that assisted with introducing nanodiamonds (NDs), high concentration H2O in electrolyte (higher than 3000 ppm) can improve the performances of LIBs. For the electrolyte with 5000 ppm H2O and a small amount of NDs, the long-cycle stability and superior reversible capacities of 950 mA h g−1 at 0.1 A g−1 after 100 cycles (130 mA h g−1 at 5 A g−1 after 10,000 cycles) have been realized, which are significantly improved in comparison with the case of sole H2O introduced in the electrolyte. The improvements can be attributed to the synergistic effect of NDs and H2O achieving highly conductive SEI network, enhanced ionic conductivity and separator wettability of electrolyte, mitigated erosion of graphite anode, and increased storage sites for Li+. This work provides an efficient method to not only boost the performances of LIBs but also reduce the cost of production in practical applications.