Abstract:
MXenes, two-dimensional transition metal carbides/nitrides, have gained significant attention
due to their unique properties that hold promise for overcoming limitations in lithium-ion battery
(LIB) technology. While graphite, the currently used anode material, offers less cyclability, its
limited theoretical capacity (around 372 mAh/g) and slow Li-ion diffusion hinder advancements
in energy and power density. Therefore, MXenes are extensively studied as promising
alternatives. Their layered structure with high hydrophilicity and surface terminations facilitates
fast Li-ion intercalation, potentially leading to higher capacities. Additionally, their metallic
conductivity is advantageous for efficient charge transport, a crucial factor for fast charging. This
study focuses on Niobium-based MXenes, which have emerged as strong candidates for LIB
anodes due to their superior reversible capacity compared to Titanium-based MXenes. In this
research we utilize DFT calculations to investigate the electronic, magnetic, and thermoelectric
properties of pristine, Mo-doped, and Te-doped Nb3C2 monolayer MXenes. Our findings reveal
that both doped structures exhibit metallic characteristics with indirect band gaps, fulfilling a
crucial requirement for electrode applications in LIBs. Doping significantly impacts electronic
and thermoelectric properties. Te-doped Nb3C2 demonstrates a larger band gap, lower seebeck
coefficient, and reduced thermal conductivity compared to Mo-doped Nb3C2. Additionally,
positive Open Circuit Voltage (OCV) values suggest favorable lithium-ion intercalation for all
materials. The calculated theoretical capacities for pristine (592 mAh/g), Mo-doped (745 mAh/g),
and Te-doped (668 mAh/g) Nb3C2 fall within a competitive range compared to V3C2 (606.42
mAh/g). These results suggest that Mo- and Te-doped Nb3C2 MXenes hold promise as anode
materials for LIBs due to their improved electronic conductivity (facilitating faster charging),
reduced operating voltage, and comparable theoretical lithium storage capacity. Unveiling the
influence of doping on MXene properties, this research strives to bridge the current gap in anode
materials, paving the way for the development of next-generation LIBs with remarkable
advancements in energy density and lifetime.
