Degradation Analysis of Li₄Ti₅O₁₂ of Lithium-Ion Battery Under Tram Operating Conditions

Lithium (Li) titanate, as an anode material for energy storage batteries, has outstanding performance in long cycles under high current/high power and safety. In order to analyze the degradation behavior of Li titanate under the specified, in this article, the Li4Ti5O12 (LTO) battery cycled under the tram operating conditions is disassembled first. From the tests results based on electrochemical voltage spectroscopy (EVS), electrochemical impedance spectroscopy (EIS), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS), different from cathode degradation resulted in traditional electric vehicle operating conditions such as new European driving cycle (NEDC) and world light vehicle test procedure (WLTP), it is shown that the capacity is degraded and the impedance is increased in the anode of LTO battery with the rupture of active material on the surface. Further investigation, the cause resulting in the degradation of the anode, is that tram operating conditions may alter the electrochemical reactions occurring within the anode, thereby changing the composition of the surface film and weakening the passivation function of the film. Such unstable and loose surface film cannot effectively isolate the contact between the electrode material and the electrolyte, as a result, the internal reaction is exacerbated further leading to capacity degradation.