Investigations on the Electroreduction of Titanium Chlorides in AlCl3‐Dimethylsulfone Electrolyte

The electrochemical behavior of TiCl 3 and TiCl 4 was studied in AlCl 3 / DMSO 2 electrolyte at 130°C. The main Ti III and Ti IV species formed in the AlCl 3 / DMSO 2 ‐based electrolyte might be TiCl ( 3 − n ) n + and TiCl ( 4 − m ) m + , respectively. The reduction of Ti IV to Ti II is a multistep process (one electron transferred in each step). The diffusion coefficient values of Ti III and Ti IV species have been calculated from voltamperometric and chronoamperometric investigations. Analysis of sampled current voltammograms indicates that the Ti IV / Ti III process is a quasi‐reversible redox system with E 1/2 close to 3.575 V vs Li + /Li and that the reduction of Ti III to Ti II might involve an electrochemical‐chemical mechanism, i.e., electron transfer followed by a destructive reaction or a disproportionation of Ti II species. In the 2 to 4 V potential range, metallic titanium deposition is not observed.