Multiscale-Designed Nanocomposite with a Fast Na⁺ Diffusion Channel for Ultra-High Rate Sodium-Ion Batteries

Abstract

The design of sodium storage materials with high power and energy density is of great significance to the development of sodium-ion batteries. Herein, a multiscale-designed nanoscale TiO2/Bi2Se3@C composite with a uniform size was prepared from bulk materials by a simple arc discharge technique, and the yield of gram grade was realized. The TiO2/Bi2Se3@C nanocomposite has a unique core–shell structure, fast Na+ diffusion channel, and abundant surface-active sites to ensure the rapid transfer of surface charge. Moreover, the introduction of TiO2 acts as a structural maintenance agent, enhancing the strength of the nanocomposite, and buffers the volume variation of the electrode together with carbon coating. The simulation results show that the nanocomposite has fast ion transfer in a sodium electrolyte system and is suitable for charging and discharging at ultra-high rates. As a result of structural engineering, the core–shell composite exhibited exceptional rate performances (460 mA h g–1 at 1 A g–1 and 335 mA h g–1 at 40 A g–1) and ultra-long cycle stability (10,000 cycles at 40 A g–1). This study shows a significant and much-needed improvement in the sodium storage performance of sodium-ion batteries by designing anode materials with an effective strategy.

Breaking Barriers: Binder-Assisted NiS/NiS2 Heterostructure Anode with High Initial Coulombic Efficiency for Advanced Sodium-Ion Batteries

“…To further understand the superior energy storage behavior of the NiS/NiS 2 @SA-g-PAM electrode and its kinetics, the CV tests were taken at different scan speeds distributed from 0.1 to 0.9 mV s –1 (Figure b). According to earlier reports, the following eqs and define the relationship between the peak current ( i ) and scanning speed ( v ) of CV curves where a and b are adjustable coefficients determined by the relationship between the sweep speed ( v ) and the current ( i ) at a particular potential.…”