Towards the reactivity of MIL-53 or Fe~Ⅲ(OH)_(0.8)F_(0.2)O_2C-C_6H_4- CO_2 versus lithium

摘要

We demonstrate here the reversible electrochemical insertion of lithium into the hybrid porous solid Fe~Ⅲ(OH)_(0.8)F_(0.2)[O_2C-C_6H_4-CO_2]. Used as an electrode in Li-half cell, this material shows a reversible redox process around 3.0V vs. Li~+/Li~o exchanging 0.6Li per formula unit with interesting capacity retention and rate capability. Moreover, it reveals an interesting feature for MOFs with large tunnels: the uptake of electrolyte molecules within their channels, which facilitates ionic transport in MOFs. Mixed valence in MOFs opens new opportunities for the elaboration of materials with tuneable properties for various applications.