Nanomaterials 2022, 12, 2825. https://doi.org/10.3390/nano12162825 www.mdpi.com/journal/nanomaterials Article Vanadium Carbide (V4C3) MXene as an Efficient Anode for Li-Ion and Na-Ion Batteries Qiong Peng 1 , Javed Rehman 2, *, Kamel Eid 3, *, Ayman S. Alofi 4 , Amel Laref 5 , Munirah D. Albaqami 6 , Reham Ghazi Alotabi 6 and Mohamed F. Shibl 7 1 Istitution of Condensed Physics & College of Physics and Electronics Engineering, Hengyang Normal University, Hengyang 421002, China 2 Department of Physics, Balochistan University of Information Technology, Engineering and Management Sciences (BUITEMS), Quetta 87300, Baluchistan, Pakistan 3 Gas Processing Center (G.P.C.), College of Engineering, Qatar University, Doha 2713, Qatar 4 Physics Department, College of Science, Taibah University, Medina 42353, Saudi Arabia 5 Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia 6 Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia 7 Center for Sustainable Development, College of Arts and Sciences, Qatar University, Doha 2713, Qatar * Correspondence: javed.rehman@buitms.edu.pk (J.R.); kamel.eid@qu.edu.qa (K.E.) Abstract: Li-ion batteries (LIBs) and Na-ion batteries (SIBs) are deemed green and efficient elec- trochemical energy storage and generation devices; meanwhile, acquiring a competent anode re- mains a serious challenge. Herein, the density-functional theory (DFT) was employed to investigate the performance of V4C3 MXene as an anode for LIBs and SIBs. The results predict the outstanding electrical conductivity when Li/Na is loaded on V4C3. Both Li2xV4C3 and Na2xV4C3 (x = 0.125, 0.5, 1, 1.5, and 2) showed expected low-average open-circuit voltages of 0.38 V and 0.14 V, respectively, along with a good Li/Na storage capacity of (223 mAhg −1 ) and a good cycling performance. Fur- thermore, there was a low diffusion barrier of 0.048 eV for Li0.0625V4C3 and 0.023 eV for Na0.0625V4C3, implying the prompt intercalation/extraction of Li/Na. Based on the findings of the current study, V4C3-based materials may be utilized as an anode for Li/Na-ion batteries in future applications. Keywords: V4C3; MXene; Li-ion battery; Na-ion battery; electrochemical energy storage; DFT 1. Introduction The everlasting consumption of fossil fuels leads to their depletion and greenhouse gas emissions, which are the primary cause of global warming [1–3]. A variety of en- deavors are currently being dedicated to addressing these issues, including gas conver- sion reactions [4,5] and utilizing sustainable energy sources (i.e., solar power [6,7], hy- drogen power [8], fuel cells [9,10], and energy storage devices [11–15]). Li-ion batteries (LIBs) and Na-ion batteries (SIBs), with their high energy, power density, and long cycle life, are among the most beneficial electrochemical energy conversion and storage tech- nologies available for smart grids, mobile electronics, and electric vehicles [16–18]. The performance of LIBs and SIBs is primarily shaped by the electrochemical properties of the anode materials [16,17]. Graphitic carbon is the universally utilized commercial an- ode material, but its low Li/Na theoretical capacity (372/25 mAh/g) and low rate capabil- ity limit its widespread, practical use [19]. Despite the significant progress in LIBs and SIBs, the earth availability of Li/Na, charge time, durability, temperature tolerance, self-discharge, and recyclability of the decayed batteries are creating a significant chal- lenge [16–22]. Therefore, developing novel anodes with high specific capacities, greater rate capabilities, and cycling longevity is imperative. MXenes are a novel class of 2D transition metal carbide/carbonitride electrodes that Citation: Peng, Q.; Rehman, J.; Eid, K.; Alofi, A.S.; Laref, A.; Albaqami, M.D.; Alotabi, R.G.; Shibl, M.F. Vanadium Carbide (V4C3) MXene as an Efficient Anode for Li-ion and Na-ion Batteries. Nanomaterials 2022, 12, 2825. https://doi.org/10.3390/ nano12162825 Academic Editor: Robert A. Evarestov Received: 28 May 2022 Accepted: 8 August 2022 Published: 17 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdic- tional claims in published maps and institutional affiliations. Copyright: © 2022 by the au- thors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attrib- ution (CC BY) license (https://creativecommons.org/lice nses/by/4.0/).