Amorphous TiO₂/C Frameworks as Intercalation Pseudocapacitance Anodes for Fast and Durable Sodium Storage

Abstract

High rate and long-life sodium-ion batteries (SIBs) are highly desirable for stationary energy storage applications. However, the practical implementations of SIBs are strictly restricted due to the shortage of satisfactory anode materials. In this study, a Fe and N co-doped amorphous TiO 2 /C composite synthesized by an MOF-derived approach fulfills the demands of kinetics and durability by stimulating intercalation pseudocapacitance. Unlike traditional crystalline materials whose pseudocapacitance behaviors are highly dependent on the surface area and the crystal structure, the amorphous TiO 2 /C composite shows fast Na + intercalation/deintercalation independent of the surface area, and it can deliver impressive capacities, decent rate capability, and excellent cyclability. The electrochemical analysis shows that intercalation pseudocapacitance is responsible for the prominent sodium storage performance of the amorphous TiO 2 /C composite. This work demonstrates that Na + intercalation can be realized in amorphous structures and is beneficial for the development of extrinsic pseudocapacitive materials.

Selenium-Doped Amorphous Black Phosphorus@TiO2/C Heterostructures for High-Performance Li/Na/K Ion Batteries

“…The high-resolution transmission electron microscopy (HRTEM) image (Figure S2b) reveals the lattice fringes of 0.35 nm, which correspond to the anatase (101) planes. 31 TiO 2 /C was then mixed with Se powders and BP crystals with two-dimensional (2D) morphology and good crystallinity (Figure S3) for ball-milling treatment to obtain the final Se-BP@TiO 2 /C. Note that the MOF-derived method used can prepare TiO 2 /C heterostructures with good performance on a large scale, while the Se-assisted ball-milling is also a commercially available technique.…”

“…21-1272 of anatase TiO 2 . The high-resolution transmission electron microscopy (HRTEM) image (Figure S2b) reveals the lattice fringes of 0.35 nm, which correspond to the anatase (101) planes . TiO 2 /C was then mixed with Se powders and BP crystals with two-dimensional (2D) morphology and good crystallinity (Figure S3) for ball-milling treatment to obtain the final Se-BP@TiO 2 /C.…”

Mn0.26V2O5·nH2O Nanoribbons with Fast Ion Diffusion Channels and High Electrical Conductivity for Intercalation Pseudocapacitive Zn2+ Storage

“…The Q c value can be determined by the y -intercept ( v –1/2 = 0 and y = 0.846), indicating that 84.6% of the total charge is from the capacitive process. Similarly, the capacitive charge can also be estimated using the k 1 – k 2 analysis (formula ) , Taking v = 1.0 mV s –1 as an example, the capacitive charge takes up 83.7% of the total charge (the inset of Figure C), which is close to the Q c value. Moreover, the capacitive charge reached the fairly high proportions of 75.7, 76.2, 79.3, and 81.6% at 0.2, 0.4, 0.6, and 0.8 mV s –1 (Figure D), which are markedly higher than those of VOH.…”

Doping-Induced Static Activation of MnO2 Cathodes for Aqueous Zn-Ion Batteries

“…A pair of incremental broad redox peaks is clearly observed in the CV curves (Figure 6a), which is the typical characteristic of pseudocapacitance. As shown in formula 1, the CV peak current (i) obeys a power-law relationship with the scan rate (v): 45,46…”

“…A pair of incremental broad redox peaks is clearly observed in the CV curves (Figure a), which is the typical characteristic of pseudocapacitance. As shown in formula , the CV peak current ( i ) obeys a power-law relationship with the scan rate ( v ): , where a b value of 1.0 represents a capacitive process, and a b value of 0.5 indicates a diffusion-controlled process. Figure b shows the log­( i )–log­( v ) plots of VMO/ZVO cathode, revealing that the b values of the cathodic and anodic peaks are 0.79 and 0.62, respectively, which suggests that the charge storage of the cathode is controlled by both capacitance and diffusion.…”