In lithium-ion batteries (LIBs), conversion-based electrodes such as transition-metal oxides and sulfides exhibit promising characteristics, including high capacity and long cycle life. However, the main challenge for conversion electrodes to be industrialized remains on voltage hysteresis. In this study, Mn3O4 powder was used as an anode material for LIBs to investigate the root cause of the hysteresis. First, the electrochemical reaction paths were found to be dominated by Mn/Mn2+ redox couple after the first lithiation from galvanostatic charging/discharging (GCD) and cyclic voltammetry (CV) measurements. Then, the voltage hysteresis was proposed to be composed of reaction overpotential (similar to 0.373 V) and intrinsic overpotential (similar to 0.377 V), which were related to the diffusion behaviors according to CV, galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS) analyses. Furthermore, results revealed that the formation of disparate phase distribution during lithiation and delithiation could be the root cause of the intrinsic overpotential of Mn3O4. These results were based on ultrahigh-resolution transmission electron microscopy (UHRTEM) and molecular dynamics (MD) simulation. It was expected that improving the diffusion behaviors of the systems could eliminate the voltage hysteresis of Mn3O4. In summary, this paper provides an explicit insight into the hysteresis for conversion-based Mn3O4 that could also be applied to other oxide systems and very crucial to reduce energy loss for commercializing oxides as anode materials in LIBs.
The investigation on the voltage hysteresis of Lithium-ion batteries with Mn3O4 anode material
Sustainable Development Goals
Abstract/Objectives
With the increasing development of the industry, people's demand for energy storage is also getting higher and higher. Under the trend of green energy and carbon reduction, the demand for the use of repetitive batteries is also increasing rapidly. Lithium batteries have replaced traditional nickel-cadmium batteries. Its extremely small size and relatively high energy density are big advatage, but if you want to further improve the performance, you need to use materials with higher energy density, and metal oxides have this feature and are non-toxic and environmentally friendly, and the earth is rich in abundance, etc. However, the voltage hysteresis will damage the energy density. This study speculates on its principle and root reason and hopes to find a solution based on this in the future.
Results/Contributions
Keywords
Lithium-ion batteryTransition metal oxideVoltage hysteresisMolecular dynamic stimulationComposition inhomogeneity