context: To investigate the failure mechanism of the overcharge protection of the TDAC, a scaled-up NCA/graphite cell was employed to reclaim enough electrolyte and electrode materials for a post-mortem analysis. The reclaimed electrolyte after overcharge was in a brownish color, which could be contributed by the dissolution of the transition metals (Co and Ni) from the cathode, the decomposition products of the electrolyte solvent, or the TDAC molecules in the harsh overcharge environment. MS, NMR and CV were used to analyse the reclaimed electrolyte in comparison with the fresh electrolyte. Fig. 5a shows a peak at a 283.2 mass/charge ratio (m/z) for both electrolytes. The MS data confirmed the existence of TDAC cation species in both electrolytes. The similar intensity of the peaks indicated that the concentration of the TDAC in the overcharged electrolyte was about the same as that in the fresh one. NMR analysis as shown in Fig. 5b also confirmed that most of the TDACs remained intact since no TDAC decomposed compounds were detected. The CV profile in Fig. 5c reveals a pair of reversible redox peaks at ∼1.35 V vs. Fc+/Fc, exhibiting no discrepancy against the fresh TDAC electrolyte. The reclaimed electrolyte was then injected into a cell with new NCA and graphite sheets. As displayed in Fig. 5d, the potential plateau at ∼4.5 V reappeared in the reassembled cell despite a lower CE and a decreased capacity.