Metal-Organic Framework Glass Anode with an Exceptional Cycling-Induced Capacity Enhancement for Lithium Ion Batteries

Metal organic frameworks (MOFs) hold great promise as high-energy anode materials for next-generation lithium ion batteries (LIBs) due to their tuneable pore structure and abundant reaction sites. However, since the pore structure of crystalline MOFs tends to collapse during lithium ion insertion and extraction, it has been a challenge to develop crystalline MOF-based anodes for high performance lithium ion batteries. Here we report a breakthrough in developing the high-performance MOF anodes. In detail, we have developed the first MOF glass anode, i.e., melt-quenched Cobalt-ZIF-62 glass anode with exceptional electrochemical performances. Compared with its crystalline counterpart, the Co-ZIF-62 glass anode exhibits significantly higher lithium storage capacity (306 mAh g^-1 after 1000 cycles at the current density of 2 A g^-1), outstanding cycling stability and superior rate performance. Amazingly, the Li-ion storage capacity of the MOF glass anode continuously rises with increasing the number of charge-discharge cycles and even tripled after 1000 cycles. We revealed the possible origin of the unusual cycling-enhanced performances of the MOF glass anode. These superior performances make MOF glasses ideal candidates for anode materials for LIBs.