TiO₂ bunchy hierarchical structure with effective enhancement in sodium storage behaviors

Abstract

Bronze phase TiO2 [TiO2(B)] has great research potential for sodium storage since it has a higher theoretical capacity and ion mobility compared with other phases of TiO2. In this case, preparing porous TiO2(B) nanosheets, which can provide abundant sodium insertion channels, is the most effective way to improve transport kinetics. Here, we use the strong one‐dimensional TiO2 nanowires as the matrix for stringing these nanosheets together through a simple solvothermal method to build a bunchy hierarchical structure [TiO2(B)‐BH], which has fast pseudocapacitance behavior, high structural stability, and effective ion/electron transport. With the superiorities of this structure design, TiO2(B)‐BH has a higher capacity (131 vs. 70 mAh g−1 [TiO2‐NWs] at 0.5 C). And it is worth mentioning that the reversible capacity of up to 500 cycles can still be maintained at 85 mAh g−1 at a high rate of 10 C. Meanwhile, we also further analyzed the sodium storage mechanism through the ex‐situ X‐ray powder diffraction test, which proved the high structural stability of TiO2(B)‐BH in the process of sodiumization/de‐sodiumization. This strategy of uniformly integrating nanosheets into a matrix can also be extended to preparing electrode material structures of other energy devices.

A Novel Hybrid Point Defect of Oxygen Vacancy and Phosphorus Doping in TiO2 Anode for High-Performance Sodium Ion Capacitor

“…However, the main challenge lies in the unsatisfactory kinetic behavior of the anode material when is assembled with the cathode material (typically active carbon, AC) [10,11]. For example, titanium dioxide (TiO 2 ) is considered as an ideal anode material due to its low cost, good cycle stability, high theoretical capacity (335 mAh g −1 ), non-toxicity and nearly zero-strain during charging and discharging process [12][13][14][15]. Nevertheless, the low conductivity (~ 10 -12 S cm −1 ) and the slow diffusion rate of Na + in TiO 2 severely limit its practical application.…”

Electron‐Extraction Engineering Induced 1T’’‐1T’ Phase Transition of Re0.75V0.25Se2 for Ultrafast Sodium Ion Storage

“…In comparison with the reported sodium‐ion anodes (FeNx@C, FeP@NC, Bi 2 Te 3 @ppy, TiNbO 5 @rGO, etc. ), [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ] the 1T’ Re 0.75 V 0.25 Se 2 electrode has very big advantages in ultra‐high rate capacity and long‐term cycling stability (Figure 3g ).…”

“…In comparison with the reported sodium-ion anodes (FeNx@C, FeP@NC, Bi 2 Te 3 @ppy, TiNbO 5 @rGO, etc. ),[44][45][46][47][48][49][50][51][52][53] the 1T' Re 0.75 V 0.25 Se 2 electrode has very big advantages in ultra-high rate capacity and long-term cycling stability (Figure3g).The reaction kinetic analysis based on CV curves was carried out at increasing sweep rates (0.2 to 1.0 mV s −1 ) to provide insight into the high-rate and long-life capabilities. As demonstrated in Figure4a, the pairs of cathodic and anodic peaks are well maintained with the increasing scan rate, suggesting a good reversible reaction in the 1T' Re 0.75 V 0.25 Se 2 electrode.…”

Defect-Induced and Synergistic Na-Ion Storage Capability of TiO2(B)@MoSe2/Carbon Trinity for Ultrafast and Ultralong Cycling

“…A comparative first-principles study showed that TiO 2 (B) can reduce the formation energy and provide the most favorable sites for Na + insertion compared with anatase and rutile TiO 2 . Theoretically, TiO 2 (B) possesses a high capacity of 335 mAh g –1 and exhibits fast pseudocapacitance behavior . However, the practical capacity of TiO 2 (B) for Na + storage is still not high enough, and its semiconductive characteristic also hinders the rate performance.…”

“…17 Theoret-ically, TiO 2 (B) possesses a high capacity of 335 mAh g −1 and exhibits fast pseudocapacitance behavior. 18 However, the practical capacity of TiO 2 (B) for Na + storage is still not high enough, and its semiconductive characteristic also hinders the rate performance. Some strategies such as heteroatom doping or incorporation of carbon into TiO 2 (B) have been adopted to improve its performance.…”