Bimetallic Sulfates A_2M(SO_4)_2?nH_2O (A = Li, Na and M= Transition Metal) as New Attractive Electrode Materials for Li- and Na-ion Batteries

摘要

Developing the next generations of Li- and Na-ion batteries relies on designing new sustainable, low-cost and safe electrode materials. In such an attempt, we investigated several series of bimetallic sulfates, among them we identified Na_2Fe(SO_4)_2?4H_2O, Na_2Fe(SO_4)_2 and Li_2Fe(SO_4)_2, which present attractive electrochemical properties against both lithium and sodium. With a potential of 3.83 V vs. Li~+/Li~0, the new lithium iron sulfate Li_2Fe(SO_4)_2 displays indeed the highest potential ever obtained for the Fe~(3+)/Fe~(2+) redox couple in an iron-based fluorine-free compound.