Nanoporous TiNb₂O₇/C Composite Microspheres with Three-Dimensional Conductive Network for Long-Cycle-Life and High-Rate-Capability Anode Materials for Lithium-Ion Batteries

Abstract

On the basis of the advantages of ideal cycling stability, high discharge voltage (1.65 V), and excellent reversibility, more and more attention has been focused on TiNbO (marked as TNO) as an anode material candidate for lithium-ion batteries. However, the poor electronic conductivity and low ionic diffusion rate intrinsically restrict its practical use. Herein, we first synthesize the TNO/C composite microspheres with three-dimensionally (marked as 3D) electro-conductive carbon network and abundant nanoporous structure by a simple spray-drying method. The microspheres are constructed by irregularly primary cubic nanoparticle units with size of 100-200 nm. The nanopores throughout the microspheres range from 1 to 50 nm. As an anode material, the prepared TNO/C composite microspheres demonstrate a prominent charge/discharge capacity of 323.2/326 mA h g after 300 cycles at 0.25 C (1 C = 388 mA g) and 259.9/262.5 mA h g after 1000 long cycles at a high current density of 5 C, revealing the ideal reversible capacity and long cycling life. Meanwhile, the TNO/C composite microspheres present ideal rate performance, showing the discharge capacity of 120 mA h g at 30 C after 10 cycles. The super electrochemical performance could be attributed to the 3D electro-conductive carbon network and nanoporous structure. The nanopores facilitate the permeation of electrolyte into the intercontacting regions of the anode materials. Carbon layers disperse uniformly throughout the 3D microspheres, effectively improving the electrical conductivity of the electrode. Hence, the prepared TNO/C composite microspheres have great potential to be used as an anode material for lithium-ion batteries.

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

“…The V‐doped TiNb 2 O 7 electrode can perform high discharge capacities of 298.48 and 171.99 mA h g −1 at 0.3 and 10C rate, respectively. Moreover, preparing the nanometer dimensional phase of TiNb 2 O 7 electrode and coating with conductive materials would be one of the most promising method to dramatically develop its energy storage advantages . As an example, nano‐TiNb 2 O 7 /carbon nanotubes electrode prepared by Guo et al can exhibit high reversible capacities of 346 mA h g −1 and 163 mA h g −1 at 0.1 and 30C rate, respectively .…”

“…48 dimensional phase of TiNb 2 O 7 electrode and coating with conductive materials would be one of the most promising method to dramatically develop its energy storage advantages. [158][159][160] As an example, nano-TiNb 2 O 7 /carbon nanotubes electrode prepared by Guo et al can exhibit high reversible capacities of 346 mA h g −1 and 163 mA h g −1 at 0.1 and 30C rate, respectively. [161] In addition, based on the low volume expansion and highly stable character derived from TiNb 2 O 7 , compositing with some anode materials with higher capacity can improve the energy density of overall LIBs.…”

TiNb 2 O 7 microsphere anchored by polydopamine‐modified graphene oxide as a superior anode material in lithium‐ion batteries

“…In case of pristine TNO in Figure C, two sharp peaks are observed at 1.68 V in the discharge process and 1.66 V in charging, which is assigned to the reduction/oxidation process of Nb 5+ /Nb 4+ . Small peaks at 1.7 V in the discharge process and 2.1 V in the charge process are related to additional Ti 4+ /Ti 3+ redox couples . Figure D reveals the dQ / dV plot of the TNO/PGO composite, which is associated with each redox reaction appearing at the same position as that of pristine TNO.…”

“…A strong insulating property results in a severe capacity drop in the fast charging/discharging related to the rate performance of the anode electrode . To enhance the conductivity of TNO, a carbon composite, which has a simple preparation process, has been considered for the modification of TNO . As a suitable carbonaceous material, 2D graphene, which has high surface area and electrical conductivity, has been attempted to be introduced for improving the electric/ionic conductivity of TNO.…”

“…16,17 To enhance the conductivity of TNO, a carbon composite, which has a simple preparation process, has been considered for the modification of TNO. 14,[18][19][20][21] As a suitable carbonaceous material, 2D graphene, which has high surface area and electrical conductivity, has been attempted to be introduced for improving the electric/ ionic conductivity of TNO. For instance, Ashish's group announced a TNO/graphene hybrid material, which showed 80% capacity retention at 16C and discharge capacity of~230 mAh g −1 at 0.1C.…”