Liquid metal activated aluminum-water reaction for direct hydrogen generation at room temperature

In light of high energy density, hydrogen has been recognized as a promising clean energy carrier to defuse the coming energy crises. Among the many technological strategies ever tried, the Al-H2O reaction is a rather favored way to produce hydrogen although it is always hindered by a layer of passive film on Al surface. Recently, a class of gallium-based room-temperature liquid metal (RTLM) is found to effectively activate the Al-water reaction which draws attentions to such an extremely simple hydrogen production method. To push forward further investigations of this newly emerging area, this article is dedicated to present an overview of the latest advancement of the hydrogen production from the RTLM activated direct Al-H2O reaction. Meanwhile, it also comprehensively interprets the mechanisms of the RTLM activated Al-H2O reaction in terms of electrochemistry, phase constituents, interface actions and energy transfer process, and then discusses four influencing factors dominating the reaction. Next, several unique phenomena of RTLM fed with Al driven by releasing hydrogen are also illustrated, offering a glimpse on the development of soft robots. In addition, theoretical and technological challenges lying behind such a hydrogen generation scheme are prospected. It is anticipated that the RTLM triggered Al-H2O reaction for an in-time and on-demand hydrogen generation will witness a ever bright future in the coming time.