Cell advanced alkaline electrolysis

Figure 7.2 Cell designs, (a) Conventional alkaline electrolysis (b) advanced alkaline electrolysis (zero gap) (c) SPE configuration (acid electrolysis).

TVvo main processes are considered to produce hydrogen from water electrolysis at quite low temperature (about 100°C). These processes are the most advanced ones and, up to now, one is already commerdafised the alkaline electrolysis cell. The second one, PEMEC, seems to be very promising, especially for coupling with renewable energy. Both systems presented below are based on the fuel cell technology assodated and described in Section 15.3. 

The materials were studied in the form of thin films. Physical and mechanical properties were determined by DSC, torsion pendulum, stress strain, stress relaxation and water contact angle measurements. Transport properties were determined in alkaline solution. Evidence of the films microporosity is seen from ion and water sorption, sodium ion self-diffusion and electrolytic conductance measurements. The latter results for lower equivalent weight samples in concentrated NaOH solutions demonstrate that these materials are promising candidates as separators in advanced alkaline water electrolysis cells. 

Different electrolysis technologies could be applied, from the commercially available method based on alkaline cells to the new advanced cells based on proton exchange membrane (PEM) and solid oxide mixtures as electrolytes. The basic schemes of these electrolysers are shown in Eig. 2.4. 

Fig. 1. Comparison of required cell voltage between conventional alkaline water electrolysis (AWE) and advanced JAWE.

---