A 25.1% Efficient Stand-Alone Solar Chloralkali Generator Employing a Microtracking Solar Concentrator

Chlorine is a large-scale chemical commodity produced via the chloralkali process, which involves the electrolysis of brine in a membrane-based electrochemical reactor. The reaction is normally driven by grid electricity; nevertheless, the required combination of voltage–current can be guaranteed using renewable power (i.e., photovoltaic electricity). This study demonstrates an off-grid solar-powered chlorine generator that couples a novel planar solar concentrator, multijunction InGaP/GaAs/InGaAsNSb solar cells and an electrochemical cell fabricated via additive manufacturing. The planar solar concentrator consists of an array of seven custom injection-molded lenses and uses microtracking to maintain a ± 40° wide angular acceptance. Triple-junction solar cells provide the necessary potential (open-circuit voltage, V_OC = 3.16 V) to drive the electrochemical reactions taking place at a De Nora DSA insoluble anode and a nickel cathode. This chloralkali generator is tested under real atmospheric conditions and operated at a record 25.1% solar-to-chemical conversion efficiency (SCE). The device represents the proof-of-principle of a new generation stand-alone chlorine production system for off-grid utilization in remote and inaccessible locations.