CNTs@C@Cu_2‐xSe Hybrid Materials: An Advanced Electrode for High Performance Lithium Batteries and Supercapacitors

Abstract

In this work, one dimensional CNTs@C anchored with Cu2‐xSe nanospheres have been prepared by a facile solvothermal method. The parameters affected the morphology of the sample are investigated. When evaluated as anode for Li ion batteries, the obtained CNTs@C@Cu2‐xSe electrode delivers enhanced electrochemical performance with high reversible capacity, better cycle stability and rate capability. After 100th cycle, a discharge capacity of 399 mAh g−1 can be achieved at 0.1 A g−1. Even at high rate of 2 A g−1, the electrode can still keep a capacity of 198 mAh g−1 after 50 cycles. In addition, the obtained CNTs@C@Cu2‐xSe shows typical faradaic redox properties and exhibits excellent specific capacity (302.7 g−1 at 1 A g−1) and prominent cycling stability (86.9 % capacity retention after 2000 cycles at 2 A g−1). The enhanced electrochemical performance can be attributed to the unique structure. The Cu2‐xSe nanospheres consist of numerous nanocrystalline, which increases the contact area between Cu2‐xSe and electrolyte, reduces the pave length as well as accommodates volume change during cycling. The amorphous carbon layer with numerous carboxyl and hydroxyl groups strengthens the adhesion between the Cu2‐xSe and the CNTs. And the CNTs can enhance the conductivity of Cu2‐xSe and alleviate the mechanical stress and strain of the electrode during charge and discharge process.

Multi-heteroatom-Doped Carbon Matrix and N-Doped Carbon Shell Double Protection Enabled Superb Stability of Nickel Diselenide for Lithium Storage

“…It can be seen from the full spectrum that C, N, O, P, Ni, and Se are presented in the samples (Figure S1), indicating the successful doping of multi-heteroatoms in the NiSe 2 @NC/rGO composite. The C 1s detailed scan shows three obvious binding energies at 284.8, 286.2, and 289.0 eV, which can be attributed to CC, C–O, and O–CO, respectively (Figure a). , This agrees well with the high-resolution spectrum of O 1s, where three binding energies of 531, 532, and 533.5 eV can be observed and ascribed to OC, P–O–C, and C–O, respectively (Figure b). − In the detailed scan of N 1s, two peaks at 398.3 and 400.0 eV corresponding to the characteristic peaks of pyridine N and graphite N, respectively, are clearly shown in Figure c. , In Figure d, there are two characteristic peaks with binding energies of 137.7 and 133.6 eV, indicating the existence of two forms of P atoms (PO and P–O). − Moreover, in the detailed scan of Ni 2p, there are two characteristic peaks at 873.6 and 856 eV together with satellite peaks at 879.5 and 861.6 eV, respectively, indicating the presence of Ni 2+ in NiSe 2 @NC/rGO composite (Figure e). ,, In Figure f, the binding energies of Se 3d 5/2 and Se 3d 3/2 are observed at 54.2 and 55.9 eV; in addition, the characteristic peaks at 59.4 eV are mainly attributed to Se–O/Se–C. − This result further solidified the formation of NiSe 2 as well as the successful doping of multi-heteroatom in NiSe 2 @NC/rGO composite.…”

Cerium Selenide Nanopebble/Multiwalled Carbon Nanotube Composite Electrodes for Solid-State Symmetric Supercapacitors

“…8 Similarly, Jin et al, with the help of the hydrothermal method, synthesized unique carbon nanotubeenfolded Cu 2−x Se nanospheres that showed a charge storage capacity of 302.7 C/g that remained stable for 4000 cycles. 9 The CoSe 2 @N-PGC/CNT electrode prepared by a metalorganic framework (MOF) exhibited a maximum storage capability of 482 mAh/g at a current rate of 0.2 A/g. 10 Similarly, Chen et al explored the supercapacitive activities of sol−gel-derived CNT@NiSe, which revealed an improved capacity of 126 mAh/g at an applied current of 1 A/g; 11 however, the obtained results are still limited by several internal aspects.…”

“…Using the hydrothermal method, Li et al enhanced the capacitance of MoSe 2 /multiwalled carbon nanotubes (MWCNTs) up to 927.25 F/g with 70.08% capacitive stability up to 3000 cycles (current rate 1 A/g) . Similarly, Jin et al, with the help of the hydrothermal method, synthesized unique carbon nanotube-enfolded Cu 2– x Se nanospheres that showed a charge storage capacity of 302.7 C/g that remained stable for 4000 cycles . The CoSe 2 @N-PGC/CNT electrode prepared by a metal-organic framework (MOF) exhibited a maximum storage capability of 482 mAh/g at a current rate of 0.2 A/g .…”

From Jackfruit Rags to Hierarchical Porous N-Doped Carbon: A High-Performance Anode Material for Sodium-Ion Batteries

“…Figure 6a displays the cyclic voltammetry (CV) curves of NPC-800 for the initial three cycles measured between 0.01 and 3.0 V with a scan rate of 0.1 mV/s. In the first cathodic scan, a tremendous irreversible peak appeared at the potential of 0.85 V, which may mostly have resulted from the irreversible reaction of the electrolyte with surface functional groups and the generation of a solid electrolyte interphase layer [40]. In addition, at a lower potential range of 0.01-0.2 V, a pair of sharp redox peaks, which corresponds to the insertion/ extraction of Na + in the NPC-800, were observed in the first cycle as well as subsequent cycles.…”