Clarification on the Gassing Behavior of Carbon‐Coated Li₄Ti₅O₁₂ at Elevated Temperature: Importance of Coating Coverage

Abstract

Lithium-ion batteries (LIBs) have become vital energy-storage devices in electric vehicles (EVs). Li 4 Ti 5 O 12 (LTO) is a promising material of LIB because of its high rate capability, cyclability, and safety compared to the graphite-based anode materials in commercial LIBs. However, one of the major concerns in LTObased LIBs is gassing, which results from the interfacial reaction between LTO and organic electrolyte solutions, unlike the reduction decomposition of an electrolyte in graphite electrodes. Carbon coating on LTO has been proposed to mitigate the gassing by preventing such side reactions, even though reports have been conflicting. In this work, there are different kinds of carbon-coated LTO deposited using the thermal decomposition of ethanol that has been investigated at elevated temperature using In Operando pressure analysis to answer the paradox of the effect of carbon coating on the gassing behavior on LTO. Our Spatial Raman Spectroscopy Analysis (SRS) shows that the carbon coating coverage is likely responsible for the discrepancy in the gassing behavior reported by other studies. Our proposed deposition process achieves complete coverage with an ultrathin 3 nm carbon coating layer which mitigates the interfacial reactions while improving electrochemical performance.

Oxalic acid-assisted preparation of LTO-carbon composite anode material for lithium-ion batteries

“…Additionally, the addition of Li 2 Ti 3 O 7 improves the specific capacity LTO/Li 2 Ti 3 O 7 composite [5,6]. Carbon coating the LTO surface can improve the electrical conductivity of LTO and isolate LTO from the electrolyte, preventing gas evolution caused by electrode decomposition, a loss of power and a loss of specific capacity [7][8][9][10]. Furthermore, carbon coating on the LTO surface improves the cycling stability of the LTO/TiO 2 electrode [11].…”

Deciphering the Interplay between Binders and Electrolytes on the Performance of Li4Ti5O12 Electrodes for Li-Ion Batteries

“…Several strategies to mitigate the gassing behavior were proposed. The use of an ultrathin carbon coating layer of LTO was demonstrated to effectively suppress the gassing behavior, resulting in enhanced rate capability [41]. Film-forming electrolyte additives such as sulfonyl imides and borates also mitigate gas evolution, passivating the LTO's surface [42,43].…”