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The oxidation and lattice distortion of spinel oxides used for magnesium-ion battery (MIB) cathodes lead to poor stability and cycling performance. Herein, the highly inverted spinel oxide Mg(Al, Fe, Mn, REE)2O4of i= 0.62 with incorporated rare-earth elements (REE) and decent specific surface area was prepared by utilizing leachate of the pelagic rare-earth-rich clays via a foamed sol–gel/calcination method. Measurements of specific capacity, cycling performance, and multiplicity performance showed that the foamed spinel exhibited distinguished electrochemical performance of MIB. At the current density of 100 mA h–1, the initial discharge and charge specific capacity were 125.7 mAh g–1and 139.7 mAh g–1, and the reversible discharge and charge specific capacities were maintained as 96.7 mAh g–1and 102.4 mAh g–1after 200 cycles of charging–discharging. The Mg-ion diffusion rate for MAFMRO was 1.08 × 10–5cm2s–1, which was significantly improved, compared to traditional magnesium spinel anodes. This work highlights an approach for modification of spinel-type cathode materials and the high-value utilization of pelagic clay resources.

Abstract: In recent years, immense interest has been paid to the biomolecular architecture with the aim of protein assembly in two dimensions on solid substrates, and the constructions of clay-protein ultrathin films (CPUFs) are particularly concerned. This paper gives an overview of the recent research concerning the protein molecules (lysozyme, papain, protamine, bovine serum albumin) immobilized on clay mineral (Na-saponite) platelets and assembled in monolayered or multilayered hybrid ultrafilms or nanofilms. Two techniques including alternate layer-by-layer (LbL) assembly and the Langmuir-Blodgett (LB) are described in detail. A variety of means, including UV-vis absorption, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, XRD, AFM and surface chemistry techniques, have been described for characterization of the films in terms of quantification of protein and clay. The result reveals that electrostatic interaction is a prominent but not the only driving force in CPUF construction. In the case of LB technique, we managed to manipulate the elementary clay mineral platelets (1.3 nm in thickness) and assemble proteins into CPUFs with the aid of surfactants, and the formation of CPUFs was monitored via surface pressure vs. time (π-t) kinetics curves and surface pressure vs. area (π-A) isotherms. The factors that influence protein adsorption on the clay layer, such as surfactants, the concentration of clay, equilibrium time, categories of protein, and injection methods, were investigated. The parameters such as protein amount (n S ), packing density (Θ), and average surface area per molecule (Ω) of deposited CPUFs were measured via method of surface chemistry and spectroscopy. By comparing the results of surface chemistry with those of adsorption experiments, we demonstrate that the surface chemistry method is a useful tool in investigating CPUFs. We also found that the water soluble protein molecules could form protein-clay hybrid monolayer over the dilute clay dispersions without addition of surfactants, and CPUFs containing elementary clay sheets and protein with great homogeneity were easily prepared by controlling certain surface pressure. To investigate the bio-catalytic performance of the immobilized lysozyme in CPUFs, we deposited CPUFs onto a cover glass, and installed the cover glass in a flow cell-grown reactor for Comamonas testosteroni (WDL7-GFP) incubation. The results show that the proliferation of WDL7-GFP is greatly suppressed by lysozyme, which demonstrates that lysozyme still retains its bioactivity after it is immobilized in the CPUFs.

ABSTRACT The fired hollow clay bricks (FHCBs) have been manufactured by firing a type of highly expansive soils, the black cotton soil (BCS), and natural volcanic ashes (VA), which were [...]