GaNb₁₁O₂₉ Nanowebs as High-Performance Anode Materials for Lithium-Ion Batteries

Abstract

M–Nb–O compounds have been considered as promising anode materials for lithium-ion batteries (LIBs) because of their high capacities, safety, and cyclic stability. However, very limited M–Nb–O anode materials have been developed thus far. Herein, GaNb11O29 with a shear ReO3 crystal structure and a high theoretical capacity of 379 mAh g–1 is intensively explored as a new member in the M–Nb–O family. GaNb11O29 nanowebs (GaNb11O29-N) are synthesized based on a facile single-spinneret electrospinning technique for the first time and are constructed by interconnected GaNb11O29 nanowires with an average diameter of ∼250 nm and a large specific surface area of 10.26 m2 g–1. This intriguing architecture affords good structural stability, restricted self-aggregation, a large electrochemical reaction area, and fast electron/Li+-ion transport, leading to a significant pseudocapacitive behavior and outstanding electrochemical properties of GaNb11O29–N. At 0.1 C, it shows a high specific capacity (264 mAh g–1) with a safe working potential (1.69 V vs Li/Li+) and the highest first-cycle Coulombic efficiency in all of the known M–Nb–O anode materials (96.5%). At 10 C, it exhibits a superior rate capability (a high capacity of 175 mAh g–1) and a durable cyclic stability (a high capacity retention of 87.4% after 1000 cycles). These impressive results indicate that GaNb11O29-N is a high-performance anode material for LIBs.

Niobium‐Based Oxides Toward Advanced Electrochemical Energy Storage: Recent Advances and Challenges

“…Highly conductive CrNb 11 O 29 nanorods also showed high reversible capacities of 343 and 228 mA h g −1 at 0.1 and 10C rate, respectively . For GaNb 11 O 29 , electrospinning derived GaNb 11 O 29 nanowebs with a theoretical capacity of 379 mA h g −1 can display high specific capacities of 264 and 175 mA h g −1 at 0.1 and 10C rate, respectively, as well as a very high first‐cycle Coulombic efficiency of 96.5% . Moreover, FeNb 11 O 29 can work as a superior anode material for LIBs, which shows a high theoretical capacity of 400 mA h g −1 .…”

“…There are numerous M–Nb–O compounds well match such requirements, such as Cr 0.5 Nb 24.5 O 62 , CrNb 11 O 29 , GaNb 11 O 29 , FeNb 11 O 29 , ZrNb 24 O 62 , Mg 2 Nb 34 O 87 , and so on. In detail, Guo et al have prepared highly conductive Cr 0.5 Nb 24.5 O 62 nanowires (Cr 0.5 Nb 24.5 O 62 ‐N) by a electrospinning technique ( Figure a,b) .…”

The Doping of FeNb11O29 as a Way to Improve Its Electrochemical Performances

“…From here to the last redox event, Nb 4+ /Nb 3+ (≈1.2 V), a diffusive contribution with a maximum at around 1.6 V (the Nb 5+ /Nb 4+ peak) can be observed. The same mechanism is reversed when Li + is extracted from the material in the anodic scan, so that the first peak is mainly diffusive (Nb 3+ /Nb 4+ ) and for the others some pseudocapacitive contribution can be observed …”

“…In the literature, it is well known the pseudocapacitive behaviour of orthorhombic Nb 2 O 5 , an intermediate phase in the conversion process from the room temperature form of Nb 2 O 5 to its high‐temperature monoclinic phase . The model we chose to explain the cyclic voltammetry curves, already used to fit the FNO CV curves describes the peak current at a particular potential as i(V)=k 1 ν + k 2 ν 1/2 , where ν is the sweep rate (mV/s) and k 1 and k 2 two constants that quantify the relative importance of the two regimes . For a semi‐infinite linear diffusion, the current varies with ν 1/2 , while for mainly capacitive processes with ν.…”

Superior Electrochemical Performance of WNb2O8 Nanorods Triggered by Ultra‐Efficient Li+ Diffusion

“…Niobium‐based oxides as anode materials for power LIBs have attracted more attentions due to its high average intercalation/de‐intercalation voltage (∼1.5 V vs. Li/Li + ) of Nb 5+ /Nb 4+ and Nb 4+ /Nb 3+ redox couples and higher theoretical specific capacity (Nb 2 O 5 ∼200 mA h g −1 and TiNb x O 2+2.5x 388–401 mA h g −1 ). Meanwhile, M−Nb‐O (M=Ti, K, V, Al, Ga, W et.al) materials usually have a higher specific capacity than Nb 2 O 5 .…”