Electrochemical Oscillation during the Galvanostatic Charging of Li₄Ti₅O₁₂ in Li-Ion Batteries

Abstract

The electrochemical signals are very important to analyze and regulate the electrochemical systems, and the electrochemical oscillation is a newly discovered electrochemical signal in Li-ion batteries (LIBs), including the voltage and current oscillations. In this work, the Li4Ti5O12 was prepared using a home-made spray-drying instrument and high-temperature sintering, and its electrochemical oscillation was studied in LIBs. The electrochemical oscillation arose when the as-prepared Li4Ti5O12 precursor was sintered in a powder (not pellet) form, and it became stronger by reducing the lithium content in Li4Ti5O12. There are two types of electrochemical oscillation as a single-period oscillation or a double-period oscillation, and they can be transformed through varying the operating temperature, the current rate, and the conductive agent ratio, which might be owing to the electrochemical kinetics of Li4Ti5O12 electrodes. Combining the sintered forms and the X-ray photoelectron spectroscopy results, whether there is some fresh surface (formed by grinding the sintered pellet) becomes a typical difference between the powder-sintered and pellet-sintered Li4Ti5O12, which would affect the nucleation step and the reaction kinetics, and we proposed a possible reaction process of the electrochemical oscillation during the galvanostatic charging process of Li4Ti5O12 in LIBs.

Modeling Li-Ion Battery Voltage Oscillations and the Impact of Exchange Current Density on Oscillation Properties

“…One important feature present in both experimental results and our findings is the asymmetry in charging and discharging oscillations (see Figure 2a). 4,19,20 In our simulations, the origin of this behavior is the exchange current density, which has important dependence on γ TS (recall eq 4). Equation 8, obtained using transition-state theory, predicts the dependence of γ TS on c̃s.…”

“…Also, the particle radius distribution used is narrower than what is suggested by electron microscopy measurements. 4,12,19 This is because of the smaller number of particles simulated, compared to the actual particles in the electrode, so polydisperse radius distributions will induce statistical fluctuations in the simulations, hampering the comparison of different simulation results.…”

“…The simulated oscillations show an inverse dependence of its frequency on the (dis)charge rate, matching experimental results. 4,19 Using simulation data, this trend is understood as a current distribution process. Operation direction influence on the oscillation properties, as seen in experimental results, 4,19,20 is also reproduced numerically.…”

“…4,19 Using simulation data, this trend is understood as a current distribution process. Operation direction influence on the oscillation properties, as seen in experimental results, 4,19,20 is also reproduced numerically. We demonstrate how the exchange current promotes this influence, an aspect still overlooked in the literature.…”

Nano/micrometer porous conductive network structure Li4Ti5O12@C/CNT microspheres with enhanced sodium-storage capability as an anode material

“…Spray drying is a method for large-scale production that is widely used in the eld of lithium-ion batteries. [21][22][23][24][25][26][27][28] However, its application in the eld of sodium-ion batteries is rarely reported. A Li 4 Ti 5 O 12 @C/rGO electrode was fabricated via the spray drying method, which shows superior sodium storage performance.…”