Nb₂CT_x MXene as High-Performance Energy Storage Material with Na, K, and Liquid K–Na Alloy Anodes

Abstract

Two-dimensional MXenes perform well as hosts in batteries, which are promising for next-generation energy storage materials. With low price and high performance, sodium (Na) and potassium (K) own the potential to replace lithium in energy storage devices, but the larger radii and dendrite growth restrict their commercialization. Herein, we successfully synthesized an accordion-like Nb2CT x MXene, whose crystal structure integrity and lamellar separation have been confirmed by characterization methods like high-resolution transmission electron microscopy (HR-TEM). Combined with solid Na and K and liquid K–Na alloy as anodes, the Nb2CT x MXene shows excellent electrochemical performance, such as high capacity retention after large current shock in tests of rate performance and long time stability for more than 500 cycles, etc. Also, the Nb2CT x MXene coupled with liquid K–Na anode performs better than that coupled with solid K for the dendrite-controlling character of the liquid electrode. The Nb2CT x MXene would boost the exploitation of more suitable host materials for Na/K-ion batteries and promote an in-depth understanding of MXenes.

24.11% High Performance Perovskite Solar Cells by Dual Interfacial Carrier Mobility Enhancement and Charge‐Carrier Transport Balance

“…[ 42 ] In addition, the hexagonal symmetry structure is also confirmed by the selected area electron diffraction (SAED) pattern (the inset of Figure S1, Supporting Information). [ 43 ] The HRTEM and SAED results further demonstrate that as‐synthesized Nb 2 CT x nanosheets have excellent crystallinity. The above results indicate that no additional oxidation and structural phase transitions occur during the LiOH and annealed treatments.…”

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“…Recently, MXenes, a class of 2D transition metal nitrides or carbides, with the formula M n +1 X n T x , where M stands for transition metals, X represents nitrogen or carbon, and T x indicates the surface terminal groups, − have captured considerable attention owing to their adjustable electronic structure produced by the versatile surface chemistries. − Because of their synergistically coupled high electrical conductivity with large interlayered spacings, MXenes functionalized by specific surface-terminated groups are tempting for attractive fast-charging energy storage − (Figure a).…”

Ti2CT2 MXene as Anodes for Metal Ion Batteries: From Monolayer to Bilayer to Pillar Structure

“…However, due to the high price of Li resources and serious security risks of Li metal anodes, LIBs might not fully meet the requirements for large-scale energy storage in the future. In recent research, other new types of metal ion batteries (such as Na + , Mg 2+ , and Al 3+ ions) have attracted great attention due to the earth-abundant content, low price, and the possibility to provide a high energy capacity. − …”