Convenient Construction of CuO/Ti₃C₂T_x Heterojunction with Strong Charge Transfer and Li Intercalation for Superior Lithium Storage

Abstract

Assembling transition-metal oxides (TMOs) and MXene with strong interfacial interactions is an effective method to overcome the drawbacks of TMOs as anodes for lithium-ion batteries (LIBs) such as large volume expansion and low conductivity. Herein, a CuO nanorod/MXene heterojunction (denoted as CuO/MXene) with a synergistic effect was constructed with a "sheet-rod-pore" hierarchical nanostructure by electrostatic self-assembly. Specifically, encapsulated CuO nanorods exert superiority in the high reversible capacity and increase the interlayer distance of the MXene matrix to explore more storage spaces. MXene could significantly boost the conductivity, accommodate volume variation, and inhibit structure collapse as a buffer network. Density functional theory (DFT) calculations confirm the strong electron transport and lithium affinity at the CuO/MXene heterointerface, elucidating the reasons for the enhanced lithium storage capacity (436.4 mAh g −1 at 500 mA g −1 ), ion diffusion kinetics, and structural stability after cycling than pure CuO and MXene. When paired with the LiCoO 2 cathode, the full cell delivers good cycling stability after 140 cycles, indicating the practical applicability of CuO/MXene. This work not only validates the robust interfacial interaction of TMO/MXene heterojunction but also explores an effective strategy to prepare promising anode materials for the next-generation LIBs.

Si@Nitrogen-Doped Carbon Nanoparticles for Lithium-Ion Battery Anodes

“…Moreover, as shown in Figure d, the pseudocapacitance contribution rises from 64.48 to 74.33% as the scan rate increases from 0.2 to 0.5 mV s –1 . This suggests that the pseudocapacitance contribution in the capacity storage of Si@NC electrode becomes increasingly important with the elevation of scanning rate, which enables the Si@NC electrode to exhibit an excellent rate capability …”

“…This suggests that the pseudocapacitance contribution in the capacity storage of Si@NC electrode becomes increasingly important with the elevation of scanning rate, which enables the Si@NC electrode to exhibit an excellent rate capability. 64 The microstructures of the Si electrode and Si@NC electrode before and after cycling have been observed using SEM and TEM images. In the initial state, the surface of the Si@NC electrode (Figure 8a) is relatively rough and fluffy, whereas the Si electrode shows a smooth and dense surface (Figure 8c).…”

Diphosphorus Center Derived from Polyoxometalate for High-Energy Lithium Storage of MXene Nanosheets

“…In the context of carbon dioxide peaking and carbon neutrality, the development of advanced energy storage technology has become a new strategic goal for all countries in the world. Lithium-ion capacitors have been widely applied in the fields of rail traffic, electric automobiles, new energy power generation, the aerospace industry, and national defense and military, owing to the superior energy and power density than those of lithium-ion batteries and supercapacitors. − Two-dimensional titanium carbides and/or nitrides (MXenes) are regarded as the ideal anode materials due to their layered structure, larger specific surface areas, high electronic conductivity, adjustable surface terminals, and abundant redox sites. − MXenes can be expressed as M n +1 X n T x ( n = 1–4), where M represents early transition elements such as Ti, V, Mo, Nb, Cr, etc; X represents C and/or N; and T x represents −OH, −O, −F, −Cl surface terminals. − The energy storage mechanism in an organic system is primarily the pseudocapacitance reaction based on the intercalation of cations in the interlayer. , The solvated shell will collapse for partial solvated cations during the charging so that the exposed atomic orbitals will hybridize with the orbitals of surface terminals . The hybridization will induce the formation of a donor band of cations, which realizes the charge transfer from cations to MXene nanosheets and weakens the double-layer effect .…”

“…In addition, the construction of heterostructures is an effective strategy to regulate the properties of two-dimensional materials. , The transition metal phosphides exhibit good lithium storage capacity owing to excellent conductivity, multielectron transfer reaction, and lower lithiation/delithiation potential. , Polyoxometalates are three-dimensional clusters composed of transition metal oxyanions, exhibiting promising energy storage performance due to high theoretical capacity, electron and proton transfer abilities, and reactive lattice oxygen. − However, the energy storage abilities are restricted by worse lithium-ion migration and smaller specific surface areas . Polyoxometalates can be decomposed into transition metal oxides and phosphides during the calcining process, which will further improve the electronic and ionic conductivity.…”