Electrochemical activity of lightweight borohydrides in lithium cells

As substitutes for graphite, the negative electrode material commonly used in Li-ion batteries, hydrides have the potential to overcome both safety and performance limits of the current state-of-the-art Li-ion cells. Hydrides can operate through a conversion process proved for some interstitial hydrides like MgH₂: M_xA_y+nLi= xM+yLi_mA, where m=n/y. Even if far from optimization, outstanding performances were observed, drawing the attention on the whole hydride family. Looking for high capacity systems, lightweight complex metal hydrides, as borohydrides, deserve consideration. Capacities in the order of 2000-4000 mAh/g can be theoretically expected thanks to the very low formula unit weight. Although the potential technological impact of these materials can lead to major breakthroughs in Li-ion batteries, this new research field requires to tackle fundamental issues that are completely unexplored. Our preliminary findings on the incorporation of borohydrides will be here presented.