High-Energy-Density LiNi_0.8Co_0.15Al_0.05O₂ and Dual-Phase LTO-R-TiO₂ Materials via a Microwave-Assisted Reaction: Alleviating the Capacity Fading Mechanism by Nanocoating of Al₂O₃ and PEDOT

Abstract

Here, we report the improved energy storage performance of lithium-ion batteries consisting of a hexagonal-layered LiNi 0.8 Co 0.15 Al 0.05 O 2 (LNCA) cathode and a spinel-type Li 4 Ti 5 O 12 -Rutile-TiO 2 (LTO-R-TiO 2 ) dualphase anode upon nanocoating of Al 2 O 3 and electronically conducting poly(3,4ethylenedioxythiophene) (PEDOT). LNCA and LTO-R-TiO 2 were prepared by rapid microwave-assisted hydrothermal (MW-HT) and solid-state (MW-SS) techniques within 10−30 min compared to conventional techniques that require >35 h. The crystal structure, lattice parameters, and microstrain (ε) of the electrode materials induced by microwave irradiation (MW-HT and MW-SS) were determined using the Williamson−Hall equation deduced from X-ray diffraction. The Raman and Fourier transform infrared spectroscopy studies delineated the existence of PEDOT and dual phases of LTO-R-TiO 2 . Field emission-scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy analyses revealed homogeneous distribution of transition-metal ions along with the polymer and Al 2 O 3 over the electrode surface. The UV−visible and DRS spectroscopies unveiled the reduction in band-gap energies (E g ) of LTO-R-TiO 2 after PEDOT coating. Indeed, the LNCA-Al 2 O 3 /PEDOT hybrid cathode exhibited an enhanced discharge capacity of 209 mAh g −1 with a Coulombic efficiency of 98% compared to the uncoated pristine cathode with a discharge capacity of 194 mAh g −1 with a Coulombic efficiency of 91%. On the other hand, the optimized LTO-R-TiO 2 /PEDOT hybrid anodes exhibited a reversible capacity of 174 mAh g −1 at 0.2 C compared to the pristine anode with a reversible capacity of 169 mAh g −1 at 0.2 C vs Li/Li + in the half-cell configuration. Besides, the LNCA-Al 2 O 3 /PEDOT||LTO-R-TiO 2 /PEDOT full cells delivered an energy density of 156.2 Wh kg −1 with excellent cyclability over 200 cycles at 1 C with a capacity retention of 90%. The FE-SEM image illustrated the absence of structural/mechanical damage in LNCA-Al 2 O 3 /PEDOT and LTO-R-TiO 2 /PEDOT electrodes after 200 cycles in the full-cell configuration. Hence, amorphous phases of the PEDOT matrix and Al 2 O 3 -coating layers tend to promote the electrical conductivity and reaction kinetics of both electrodes. Therefore, this work provides an energy-efficient and cost-effective synthesis approach driven by microwave irradiation for the development of high-energy-density lithium-ion batteries. KEYWORDS: lithium-ion batteries, microwave-assisted synthesis, Al 2 O 3 and poly(3,4-ethylenedioxythiophene) coating, dual coating, LiNi 0.8 Co 0.15 Al 0.05 O 2 -Al 2 O 3 /PEDOT, LTO-R-TiO 2 /PEDOT hybrid electrodes

Revealing the effect of substitutional cation doping in the A-site of nanoscale APbI3 perovskite layers for enhanced retention and endurance in optoelectronic resistive switching for non-volatile bipolar memory devices

“…59 In our MW-ST method, autogenous pressure is generated inside the vessels, favouring quick nucleation. 60 Fig. 10a shows the schematic illustration of the variation in morphology with respect to various cations substituted in the A-site of the metal halide perovskite Fig.…”

“…These morphologies demonstrate the advantages of both cubelike and rod-like structures enabling high surface area and better particle-particle interconnection, which in turn offers prompt electron transport, favouring the electrochemical switching performance. [58][59][60][61] Therefore, we can conclude that various organic and inorganic cations doped into the A-site of APbI 3 perovskite lattice influence the morphology of metal halide perovskites under MW-ST conditions, owing to the disparity in their ionic radii. The variation in morphology with respect to various cations is schematically illustrated in Fig.…”

Sulfonate Functionalized Turbostratic Carbon Derived from Borassus flabellifer Flower: A Ultrathin Protective Layer to Mitigate the Dendrite Formation on the Metallic Lithium Anode

“…This results in the dendrites penetrating the separator causing a short circuit of the LMBs hindering its practical application in LMBs. Moreover, through Li stripping-plating activities the Li-metal anode suffers an infinite volume change particularly during the plating phase, which leads to severe internal stress and strain fluctuation. , To overcome these challenges, several strategies, such as mechanically increasing the Li surface area, nanocoating of stabilized Li-powder, Li-alloy, and Li-metal hybrid anodes, using solid electrolytes with a high Young’s modulus and introducing additives, such as SO 2 , CO2, alkali-metal ions, vinylene carbonate (VC), and fluoroethylene carbonate (FEC), into the electrolytes has been demonstrated. − Among them, the SO 2 and CO 2 additives are effective at modifying the nature of the solid electrolyte interface (SEI) film that reacts primarily with the Li-metal, thereby enabling the formation of an SEI that prevents further electrolyte degradation on the Li surface. − …”