Electrochemical characterization of TiNb₂O₇ as anode material synthesized using microwave‐assisted microemulsion route

Abstract

TiNb 2 O 7 materials were synthesized via a microwave-assisted microemulsion technique and a conventional solid-state reaction route. Microwave-assisted microemulsion process produced TiNb 2 O 7 powders with small particle sizes (50-100 nm) and increased surface area (22.4 m 2 /g) in comparison to the samples synthesized from solid-state method. Micelles in the microemulsion acted as nano-reactors and confined the grain growth of TiNb 2 O 7 . The microwaveassisted microemulsion-derived TiNb 2 O 7 powders presented a high discharge capacity of 333.2 mAh/g at 0.1C. The materials also delivered 94.8% retention at 5C after 100 cycles. The solid-state derived samples only processed the 283.2-mAh/g discharge capacity at 0.1C with 83.2% retention at 5C after 100 cycles. The amended capacity and cyclability of microwave-assisted microemulsionderived TiNb 2 O 7 resulted from the augmented Li + diffusion and the diminished charge transfer resistance. It was also found that the microwave-assisted microemulsion-derived TiNb 2 O 7 delivered 208 mAh/g discharge capacity at 10C, which was higher than solid-state derived samples (92 mAh/g). The improved capacity was owing to the enhancement in pseudocapacitive contribution.Present research indicated that the microwave-assisted microemulsion method effectively enhanced the electrochemical performance of TiNb 2 O 7 powders.

Plasma-Induced Defect Engineering in TiNb2O7 for Boosting Lithium-Ion Diffusion

“…For TNO, the broad peak at around 1.67/1.46 V in the first cycle at 0.1 mV·s –1 corresponds to the Nb 5+ /Nb 4+ redox pair, while the shoulder peak at around 1.69 V may be due to the coexistence of polymorphic niobium structures in TNO (coplanar octahedra) . The broad peak at around 1.92/1.85 V corresponds to the Ti 4+ /Ti 3+ redox pair . In addition, the convex peak in the 1.0–1.4 V range can be attributed to the valence change of Nb 4+ /Nb 3+ .…”

“…39 The broad peak at around 1.92/1.85 V corresponds to the Ti 4+ /Ti 3+ redox pair. 40 In addition, the convex peak in the 1.0−1.4 V range can be attributed to the valence change of Nb 4+ /Nb 3+ . The peaks corresponding to the Nb 5+ /Nb 4+ redox pair appear at around 1.70/1.49 V for PTNO relative to TNO, with a significantly lower voltage difference (0.19 V) than for TNO, indicating improved polarization after hydrogen plasma bombardment, which would contribute to the charge transfer rate and lithiumion diffusion kinetics.…”

Microwave‐assisted synthesis and electrochemical characterization of TiNb2O7microspheres as anode materials for lithium‐ion batteries

“…The energy conversion process is considered to enhance the reaction rate of compound formation. Thus, microwave‐assisted synthesis improves the phase purity and crystallinity of TiNb 2 O 7 powders 30,34,36 . The sample is identified to possess the Wadsley–Roth shear structure with C 2/ m space group 36 …”

“…Thus, microwave-assisted synthesis improves the phase purity and crystallinity of TiNb 2 O 7 powders. 30,34,36 The sample is identified to possess the Wadsley-Roth shear structure with C2/m space group.…”

“…In this study, a novel microwave‐assisted solvothermal method is adopted to develop uniformly distributed spherical particles. Microwave irradiation is chosen to impart both energy and time savings in the developed process 32–35 . The influence of microwave irradiation on the physical and electrochemical properties of TiNb 2 O 7 powders is systematically analyzed by comparing those of the solvothermal synthesized TiNb 2 O 7 powders.…”