Carbon coated 3D Nb₂O₅ hollow nanospheres with superior performance as an anode for high energy Li-ion capacitors

Abstract

Li-ion capacitors (LICs) are assembled by a lithium-ion battery-type (LIB) anode and a capacitor-type cathode, but their power density is limited by the battery anode. Looking for high electrochemical performance...

Three-Dimensional Cross-Linked Nb2O5 Polymorphs Derived from Cellulose Substances: Insights into the Mechanisms of Lithium Storage

“…It is worth noting that the surface areas of the T-, M- and H-Nb 2 O 5 samples are too low to be measured, as both the particles and pores grow larger with increasing heating temperatures. In general, the 3D cross-linked hierarchical structures are able to prevent severe aggregation and provide efficient transport paths for electrons and ions because the cross-linked particles favor continuous electron transportation and the intergranular pores allow easy transport of electrolyte and ion diffusion, which would be beneficial for fast kinetics and high capacity. , In addition, HR-TEM and selected area electron diffraction (SAED) are performed to obtain more crystalline information of the Nb 2 O 5 polymorphs. For the crystalline Nb 2 O 5 obtained at 500 °C, the lattice spacings of 3.12 and 3.93 Å are assigned, respectively, to the (100) and (001) lattice planes of the TT-Nb 2 O 5 (Figure c).…”

“…Moreover, the interconnected channels in the 3D cross-linked structures are conducive to alleviate volume expansion during Li + intercalation into the lattices. 23 Generally, 3D Nb 2 O 5 electrode materials are fabricated through a colloidal crystal templating strategy, 11,24,25 but the experimental processes are rather complex and uneconomical. Biomimetic synthesis is a facile route to fabricate desired materials that inherit the unique and intricate macro-tonanoscale structures of the related bio-substance, 26−29 which gives a solution to obtain functional materials with 3D crosslinked network structures easily and economically.…”

“…Moreover, the interconnected channels in the 3D cross-linked structures are conducive to alleviate volume expansion during Li + intercalation into the lattices . Generally, 3D Nb 2 O 5 electrode materials are fabricated through a colloidal crystal templating strategy, ,, but the experimental processes are rather complex and uneconomical.…”

Highly [001]-oriented N-doped orthorhombic Nb2O5 microflowers with intercalation pseudocapacitance for lithium-ion storage

“…S5 † that the rate capacity of the N-Nb 2 O 5 anode is also comparable to those of some other reported niobium oxide-based anodes, especially at high current density. 31,45,[50][51][52][53][54] The rate capacity of the anode is decided by the kinetics of electron transfer, which is investigated using electrochemical impedance spectroscopy (EIS) (Fig. 6b).…”

Advanced and Emerging Negative Electrodes for Li-Ion Capacitors: Pragmatism vs. Performance

“…The combination of carbon materials with T-Nb 2 O 5 is considered to be the most effective way to overcome the poor electronic conductivity [48][49][50]. Therefore, Li et al synthesized porous Nb 2 O 5 @C hollow nanospheres (3-D Nb 2 O 5 @C), where the hollow spheres allowed shortening of the ion diffusion distance and effectively buffered volume expansion [51]. The final LIC with the electrode comprising GNC (graphitic N-doped carbon)//Nb 2 O 5 @C demonstrated an energy density of 96.8 Wh kg −1 at 435.5 W kg −1 , a power density of 41 kW kg −1 at 12.6 Wh kg −1 and a high-capacity retention of 75% after 3000 cycles.…”