公益社団法人 日本金属学会

The hydrogen storage systems requirements for stationary and vehicular application are different and as such the materials requirements to meet the systems challenges are specific. The system weight is not of much concern in stationary applications, as such the material gravimetric capacity is not the most important parameter. However, the conformability and low weight both are desired for mobile applications. Various materials have been researched in the group at IITB like metal hydrides, complex and chemical hydrides. Intermetallic hydrides and solid solutions with industrial grade materials have been studied. The alloys of Fe, Ti, Zr, Cr, V etc have been studied and the impact of the different additives have been studied. Chemical hydrides including ammonia borane(AB) has been studied in great detail. AB has high gravimetric capacity of 19.6wt%, however suffer with sluggish kinetics, unwanted side products etc. These issues have been addressed by using various support materials and catalysts. The different support materials which interact with either hydridic or protic hydrogen have different reaction mechanisms and different reaction products. Studying the reaction mechanisms subjected to different reaction conditions provides a better control over the pathway and thus the byproducts. A detailed study on AB in presence of different support materials has shown suppression of undesired products, enhancement in kinetics and increased hydrogen release at lower temperatures. With the materials investigated the systems have been designed and will be integrated for various applications. The major challenge in systems design is the thermal management. Various techniques to enhance heat transfer from and to the hydrogen storage system have been devised and studied. Different configurations of heat exchangers have been simulated and been fabricated to obtain better and faster absorption and desorption in such systems.