Building a Stable Plateau-Type Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> Anode Interface toward Advanced Sodium-Ion Batteries
Zhenming Jiang, Haifeng Ke, Yanlei Zhang, Yanlei Zhang, Linwei Li, Feng Wang, Jidao Li, Jianying Huang, Yanyan Zhang, Yanyan Zhang, Yinzhu Jiang, Binmeng Chen, Yuxin Tang
Abstract
Layered structure Na 2 Ti 3 O 7 with a suitable sodiation plateau potential (∼0.3 V vs Na + /Na) is a promising anode for highly safe sodium-ion batteries (SIBs). However, the practical use of Na 2 Ti 3 O 7 is hindered by the unstable interface that forms between the anode and electrolyte leading to issues such as low initial coulombic efficiency (ICE) and cycling instability. Herein, we introduce tetraethyl orthosilicate (TEOS) as an electrolyte additive that can spontaneously and effectively react with the main component of the detrimental surface corrosion layer (sodium hydroxide, etc.) to form a protective film on the Na 2 Ti 3 O 7 anode. The Na 2 Ti 3 O 7 anode exhibits an enhanced capacity from 134.8 to 167.1 mAh g –1 at 0.1 A g –1, along with an increase in capacity retention from 56.1 to 83.9% after 250 cycles at 0.2 A g –1 . This work provides a straightforward protection strategy to address the unstable interface issues, rendering sodium titanate as a promising anode material to achieve practical application in the future.