Controllable Pulse Reverse Electrodeposition of Mesoporous LixMnO2 Nano/Microstructures with Enhanced Electrochemical Performance for Li-ion Storage

• Published in: ACS applied materials & interfaces 2019-06
• Main Authors: Behboudi-Khiavi, Sepideh, Javanbakht, Mehran, Mozaffari, Sayed Ahmad, Ghaemi, Mehdi
• Format: Article
• Language: English
• ISSN: 1944-8252
• DOI: 10.1021/acsami.9b05179

Given the ever growing demand of EVs and renewable energies, addressing the poor cyclic stability of lithium manganese dioxides is an urgent challenge. In this study, pulse reverse current as the driving force of a one-pot anodic electrodeposition was exploited to design the physicochemical and electrochemical characteristics of lithium manganese dioxides as cathode materials of Li-ion battery. The pulse reverse parameters including the span of anodic and cathodic current applying (ta and tc) and frequency (f') were systematically modulated to determine the optimized values through the monitoring of the physicochemical properties using XRD, TGA/DSC, FE-SEM, TEM, EDS, Raman spectroscopy, N2 adsorption/desorption isotherms, ICP/OES as well as electrochemical properties using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge at different currents. Based on the results, Li0.65MnO2 synthesized using ta = 95 ms, tc = 5 ms, f' = 8.33 Hz at the constant magnitude of anodic peak current density of 1 mA dm-2, was determined as the optimized sample. The optimized lithium manganese dioxide rendered the superior electrochemical performance delivering the initial discharge capacity of 283 mAh g-1 counted for 96.4% of the theoretical discharge capacity, preserving 88.3% of this capacity after 300 cycles at 0.1 C and in the meantime was able to release the discharge capacity of 115 mAh g-1 even after cycling at the higher current of 10 C. The superior electrochemical behavior of Li0.65MnO2 was attributed to the exclusive hierarchical urchin-like morphology as well as mesoporous nano/microstructures having notably high BET surface area of 320.12 m2 g-1 alongside mixed phase α/γ structure owing to the larger 2 × 2 tunnels which offer more facile Li+ diffusion.