Facile Synthesis of SnNb₂O₆@C Composite with Ultrathin Carbon Layer as Anode Materials for High‐Performance Sodium‐Ion Batteries

Abstract

Niobium‐based oxides have attracted a lot of attention as anode materials for sodium‐ion batteries (SIBs) due to their high theoretical specific capacity, excellent rate capability and exceptional safety. However, their poor intrinsic electronic conductivity and sluggish sodium ions diffusion kinetics severely hinder their practical applicability. Here, SnNb2O6@C was successfully prepared by a simple solid‐state reaction technique coupled with carbon coating. HRTEM images show that the SnNb2O6@C particles are covered with uniformly ultrathin amorphous carbon layer of about 1.8 nm, thus improving the electronic conductivity and diffusion coefficient of sodium ions. As anode for SIBs, the as‐obtained SnNb2O6@C material exhibits excellent specific capacity (369 mAh g−1 at a current density of 50 mA g−1) and remarkable rate performance (177 mAh g−1 at 1000 mA g−1), which indicates its good prospect in practical application.

Progress and Prospect of Bimetallic Oxides for Sodium-Ion Batteries: Synthesis, Mechanism, and Optimization Strategy

“…(m) Cycling stability of SnNb 2 O 6 @C electrode at 0.5 A g –1 . Reprinted with permission from ref . Copyright 2022 Wiley-VCH.…”

“…The composite exhibited good electrochemical properties with a capacity of 377 mAh g −1 at 0.02 A g −1 after 50 cycles as shown in Figure 14a− 340.2 mAh g −1 at 0.025 A g −1 and high rate capability as shown in Figure 14f−h. 77 Liu et al 134 prepared a micrometer-scale SnNb 2 O 6 @C composite by solid-state reaction and hightemperature pyrolysis using glucose as the carbon source (Figure 14i−k). The SnNb 2 O 6 @C anode showed stable cycling performance (203.8 mAh g −1 after 300 cycles at 0.05 A g −1 , 102.6 mAh g −1 after 800 cycles at 0.5 A g −1 ) and excellent rate performance (177 mAh g −1 at 1 A g −1 ).…”