(405c) The RelHy Project: Durability and Efficiency of High Temperature Steam Electrolysis

High temperature electrolysis has been demonstrated in the 80's by Dornier using tubular ceramic cells as a promising hydrogen production mean. In the recent Hi2H2 project, up-graded SOFC cells, single repeating units (SRUs) and short stacks have been operated in the electrolysis mode leading to results in complete agreement with North American and Japanese ones. Hydrogen production rates up to 0.1 gH2cm-2 hr-1, corresponding to 3.6 Acm-2 at 950°C at the cell level, have been achieved.

However, if these impressing performances confirm the high potential of Solid Oxide Electrolyser Cell (SOEC) technology, they are also associated with high degradation rates compromising market entrance. The RelHy project aims at identifying and overcoming these degradation mechanisms. For such purpose, several instrumented SRUs and short stacks are operated in parallel according to a defined common testing protocol. A special attention is paid to interconnect protective and contacting layers, to sealing and to cell materials. These tests are complemented by extensive post-test characterisations and are simulated by FE-CFD model integrating inputs from micro-modelling in order to take into account microstructure evolution effects in all SRU's materials.

First results obtained with traditional interconnect, protective layer, contact layer, sealing and cell materials are presented and discussed.