Ahmad Majed1,Chaochao Dun2,Jeffrey Urban2,Michael Naguib1
Tulane University1,Lawrence Berkeley National Laboratory2
Ahmad Majed1,Chaochao Dun2,Jeffrey Urban2,Michael Naguib1
Tulane University1,Lawrence Berkeley National Laboratory2
Two-dimensional (2D) transition metal borides (MBenes) were theoretically predicted to have high electric conductivity and high Li-ion capacity. It was predicted that Mo<sub>2</sub>B<sub>2</sub> 2D nanosheets are stable and possible through exfoliation of Mo<sub>2</sub>AlB<sub>2</sub>. However, Mo<sub>2</sub>AlB<sub>2</sub> is a metastable phase that cannot be directly synthesized. In addition, MoAlB is the only thermodynamically stable phase in the Mo−Al−B system. Partial deintercalation of Al from MoAlB was reported before using different topochemical strategies, such as NaOH, HF, and HCl-LiF. However, their electrochemical performance has not been studied before. In this study, we report on the successful etching of MoAlB to Mo<sub>2</sub>AlB<sub>2</sub> and their electrochemical performance as electrode materials for Li-ion batteries for the first time. The preliminary results show an initial significant enhancement in Li storage from MoAlB to Mo<sub>2</sub>AlB<sub>2</sub> where the specific capacity increased from 50 to 200 mAh/g when tested at a specific current of 20 mA/g. The Mo<sub>2</sub>AlB<sub>2</sub> sample was milled after etching and the electrochemical performance showed further increase to 300 mAh/g at same specific current. Results from <i>ex situ</i> X-ray diffraction and photoelectron spectroscopy to shed light on the electrochemical lithiation mechanisms will be discussed.