Enhanced Electrochemistry of Carbon Supported Functionalized Nanocomposite Cathode for Aqueous Lithium‐ion Batteries

Abstract

A novel carbon supported LiMn 2 O 4 nanocomposite framework has been explored to resolve multiple barriers associated with lithium manganese oxide cathodes for aqueous LIB systems. Here, we have successfully synthesized an architecturally stable AlF 3 À LiMn 2 O 4 /rGO composite with improved electron transfer kinetics and CV peak currents proportional to the square root of scan rate. The synergy between graphene and aluminium trifluoride enhances the intrinsic electrochemical properties of pristine LiMn 2 O 4 (LMO) and reduced Mn + 3 dissolution. The unique composite effectively reduced Li + diffusion distances with less polarization as it effectively accommodates the structural transformation during Li + ion charge and discharge. The electrochemical interrogation revealed faster charge transportation and decrease in charge transfer resistance due to inhibition of the pronounced pileup of Li + ions and undesired Mn 3 + ions on the surfaces. The electrochemical performances were tested in LiNO 3 aqueous electrolyte and the cell delivered a capacity of 90 mA h g À 1 based on the total weight of the active electrode materials. This aqueous LIB cathode system provides a promising alternative for safe, cost-effective and scalable energy storage with tolerance against misuse.

Spectroscopic and Electrochemical Exploration of Carbon-Infused Intercalation-Type Spinel Composite for Aqueous Systems

“…The line shape of the two spectra shows very strong similarities and is consistent with what has been published in the literature with regards to MWCNTs ( Varga et al, 2017 ). The main peak at ∼285 eV BE is due to C-C sp ( Xinga et al, 2018 ) bonds, while the shoulder on its high BE side is due to sp ( Willenberg and Ross, 2020 ) carbon bonds. The difference between the two spectra is that C/LMO shows a more pronounced peak at 289 eV BE, which is attributed to C=O bonds ( Varga et al, 2017 ).…”

“…The insert shows the high-resolution TEM (HRTEM) micrograph with spacing of Ca. 0.14 nm and in-plane (0–110) lattice, indicative of high crystallinity ( Willenberg and Ross, 2020 ). This in turn contributes significantly to the Li + diffusion through the electrolyte whilst structural integrity is maintained.…”

“…During the redox process, the Mn 3+/4+ facilitates reversible Li + diffusion reactions between electrodes. This process is promoted in an aqueous solution where Li + drives the reaction (3) to the left, producing a stable environment for the intercalation compound ( Willenberg and Ross, 2020 ). …”

“…The C/LMO and C/LFMPO was obtained after calcination with the purified MWCNT at 600 °C as depicted in Figure 1 . The process involved mixing 2 mg of the activated multi-walled carbon nanotubes to both LMO and LFMPO respectively ( Willenberg and Ross, 2020 ). The molar ratio was kept at 4:1.…”

“…This is due to their high-energy densities, rechargeability, and compact and light-weight nature, making them extremely consumer friendly ( Xinga et al, 2018 ; Ma et al, 2022 ). Aqueous-based electrochemical systems are emerging as strong contenders for non-aqueous systems with distinct advantages ( Willenberg and Ross, 2020 ) such as cost efficiency, non-toxicity, and stability at high temperature. The stable voltage window of aqueous electrolytes is, however, restricted to <1.5 V due to the slim potential window of water.…”