To implement appropriate recycling methods for lithium-ion batteries and estimate the current market value of the re-extracted material it is important to know the exact chemical composition of the batteries. This master thesis shows the development of a method to determine the elements Al, Li, Ni, Mn and Co of the cathode material of lithium-ion batteries via wet chemical analysis. Therefor a cathode material of known composition was used. The probed cathode persisted thereby of LiMn1/3Ni1/3Co1/3O2 besides the main component aluminium as well as minor amounts of various organic binders. To reach the goal of an optimal chemical digestion regarding reagents, period and temperature the cathode material was crushed, annealed and afterwards digested. The hence solubilized elements were measured by the flame atomic absorption spectrometer, whereupon the optimal adjustments of the device were a matter of consequences and possible matrix effects were considered. Besides the display of the most adequate digestion as well as the ideal flame conditions also the error sources and influences were pictured. Trough the evaluation of the results the aqua regia and inverse aqua regia digestion shaped up to be proper ways for the probed material.