研究目的

Understanding of deterioration processes and mechanisms (i.e., so-called aging) requires analytically accurate examination of aged cells. Changes in the distribution of lithium or transition metals in the LIB cells can in?uence their cycle and calendar life signi?cantly.

研究成果

The spatially-resolved quantitative analysis of lithium, nickel, cobalt and manganese on cycled anodes by LA-ICP-OES was successfully applied for the post-mortem examination of LIB electrodes. The quanti?cation was performed by using self-prepared matrix-matched standards; correlation coef?cients higher than r2 = 0.99 could be achieved with reasonably low standard deviations. The investigation of electrochemically treated carbonaceous anodes revealed a homogeneous lithium distribution on electrochemically aged electrodes. The amounts and distribution of transition metal deposition could be analyzed using the LA-ICP-OES setup, and revealing homogenous distribution of all three investigated transition metals (manganese, cobalt and nickel).

研究不足

The highest lithium concentration of 3 wt% is calculated with NCM111, thus the highest standard for Ni is 8.6 wt%, for Co 8.7 wt% and for Mn 8.1 wt%, respectively. The preparation of standards, in the sense of matrix matched, is limited to a reasonable amount of NCM. The highest amount of NCM for graphitic anodes was set to 3 wt%. Some of the results are subject of extrapolation as the measured signals are above the calibration and no matrix-matched standards are accessible for such high concentrations.