Predicting the Pseudocapacitive Windows for MXene Electrodes with Voltage-Dependent Cluster Expansion Models
- Pennsylvania State Univ., University Park, PA (United States); Pennsylvania State University
- Pennsylvania State Univ., University Park, PA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pennsylvania State Univ., University Park, PA (United States)
- Murata Manufacturing Co., Ltd., Kyoto (Japan)
MXene transition-metal carbides and nitrides are of growing interest for energy storage applications. These compounds are especially promising for use as pseudocapacitive electrodes due to their ability to convert energy electrochemically at fast rates. Using voltage-dependent cluster expansion models, we predict the charge storage performance of MXene pseudocapacitors for a range of electrode compositions. M3C2O2 electrodes based on group-VI transition metals have up to 80% larger areal energy densities than prototypical titanium-based (e.g., Ti3C2O2) MXene electrodes. We attribute this high pseudocapacitance to the Faradaic voltage windows of group-VI MXene electrodes, which are predicted to be 1.2 to 1.8 times larger than those of titanium-based MXenes. The size of the pseudocapacitive voltage window increases with the range of oxidation states that are accessible to the MXene transition metals. Here, by similar mechanisms, the presence of multiple ions in the solvent (Li+ and H+) leads to sharp changes in the transition-metal oxidation states and can significantly increase the charge capacity of MXene pseudocapacitors.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Computational Materials Education and Training (CoMET) NSF Research Training program
- Grant/Contract Number:
- SC0018646; AC52-07NA27344
- OSTI ID:
- 1779438
- Journal Information:
- ACS Applied Energy Materials, Journal Name: ACS Applied Energy Materials Journal Issue: 4 Vol. 4; ISSN 2574-0962
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English