Surface nitridation of Li4Ti5O12 by thermal decomposition of urea to improve quick charging capability of lithium ion batteries

Jihyun Jang,Ji Heon Ryu,Tae Hun Kim

doi:10.1038/s41598-021-92550-z

Abstract

As the application of lithium-ion batteries in electric vehicles increases, the demand for improved charging characteristics of batteries is also increasing. Lithium titanium oxide (Li4Ti5O12, LTO) is a negative electrode material with high rate characteristics, but further improvement in rate characteristics is needed for achieving the quick-charging performance required by electric vehicle markets. In this study, the surface of LTO was coated with a titanium nitride (TiN) layer using urea and an autogenic reactor, and electrochemical performance was improved (initial Coulombic efficiency and the rate capability were improved from 95.6 to 4.4% for pristine LTO to 98.5% and 53.3% for urea-assisted TiN-coated LTO, respectively. We developed a process for commercial production of surface coatings using eco-friendly material to further enhance the charging performance of LTO owing to high electronic conductivity of TiN.

Highlights

As the application of lithium-ion batteries in electric vehicles increases, the demand for improved charging characteristics of batteries is increasing
Because lithium-ion batteries (LIBs) exhibit a higher capacity and superior power characteristics compared to other conventional secondary batteries, most energy storage and conversion systems used in electronic devices are being replaced by LIBs
When the amount of urea used in the surface coating increased, the powder color became darker, indicating that the darkness of color is related to the thickness of the coating layer on the surface of LTO (Fig. 1a–c)

Summary

Introduction

As the application of lithium-ion batteries in electric vehicles increases, the demand for improved charging characteristics of batteries is increasing. Lithium titanium oxide (Li4Ti5O12, LTO) is a negative electrode material with high rate characteristics, but further improvement in rate characteristics is needed for achieving the quick-charging performance required by electric vehicle markets. We developed a process for commercial production of surface coatings using eco-friendly material to further enhance the charging performance of LTO owing to high electronic conductivity of TiN. A study has shown that coating the LTO surface with highly electric-conductive Ti–N via heat treatment at a high temperature using NH3 gas improves the cell performance (electronic conductivity of Ti–N: 4000–55,000 S cm−1)[25,26,27]. The urea-treated LTO demonstrated a uniform coating layer without changes to its crystal structure as well as improved power characteristics compared to conventional materials

Methods

Results

Conclusion