In order to investigate side products that may form during the conversion of DHA to DHAQ, a DHA negolyte was oxidized and species in the negolyte were tracked during the conversion via LC-MS. The results are presented in Figure and indicate that the dimer is oxidized by homogeneous chemical reaction(s) even when it is left under OCV. In addition to the formation of DHAQ (m/z = 239.03), other previously unexplored species that have m/z = 461.07, 463.08, and 477.08 also grow. Based on Figure , the subsequent electrochemical oxidation process enables the formation of DHAQ from the decomposed species. Nevertheless, the residual species (m/z = 463.08 and 479.08) imply that the regeneration process fails to convert all the dimer to DHAQ; in other words, the DHA dimer is irreversibly decomposed to these species, leading to a permanent capacity loss. Scheme 3: Proposed molecular structures with m/z values found by LC-MS analysis and the hypothesized DHA dimer decomposition pathways. Scheme 3 depicts proposed molecular structures with m/z values found by LC-MS analysis and the hypothesized DHA dimer chemical decomposition pathways. The high concentration of hydroxide ions facilitates the deprotonation of methine groups in the (DHA) 2 (2), thus driving the electrochemical desaturation to produce 3, which may be related to the voltage plateau starting at 0.4 V in Figure . 3 can be oxygenated to form 4 and 8. The compounds 3, 4, 8 can undergo dehydrogenative cyclization reactions to produce 6, 5, 7, respectively; corresponding m/z values have been detected from the LC-MS experiments. However, it is still unclear whether 4-8 were generated during the oxidation process in electrochemical flow cells then detected by the LC-MS experiments or produced under LC-MS experiment conditions in the presence of oxygen, as 4-8 were mainly observed in Samples 1 and 2. For Sample 3, the intensity of 1 increased whereas the intensity of 4, 7, and 8 dropped. Nevertheless, we cannot rule out that 4-8 were further electrochemically oxidized to form polyfused aromatic species that became aqueous-insoluble and precipitated on electrodes or other cell parts, thus less likely to be detected through LC-MS experiments. Further mechanistic insight needs additional study.