A strategy used to design high capacity (>200 mAh g−1), Li2MnO3-stabilized LiMO2 (M = Mn, Ni, Co) electrodes for lithium-ion batteries is discussed. The advantages of the Li2MnO3 component and its influence on the structural stability and electrochemical properties of these layered xLi2MnO3·(1 −
				x)LiMO2 electrodes are highlighted. Structural, chemical, electrochemical and thermal properties of xLi2MnO3·(1 −
				x)LiMO2 electrodes are considered in the context of other commercially exploited electrode systems, such as LiCoO2, LiNi0.8Co0.15Al0.05O2, Li1+xMn2−xO4 and LiFePO4.

Li2MnO3-stabilized LiMO2 (M = Mn, Ni, Co) electrodes for lithium-ion batteries

https://dr.ntu.edu.sg/bitstream/10356/96770/1/30.%20Application%20of%20Layered%20Double%20Hydroxides%20for%20Removal%20of%20Oxyanions.pdf

Application of layered double hydroxides for removal of oxyanions: A review

A selective-control hydrothermal method has been developed in the preparation of α- and β-MnO2 single-crystal nanowires. The crystal structure and morphology of the final products can be influenced by the concentration of NH4+ and SO42-.

Selected-Control Hydrothermal Synthesis of α- and β-MnO2 Single Crystal Nanowires

Recovery and recycling of lithium: A review

The Global Energy Assessment (GEA) brings together over 300 international researchers to provide an independent, scientifically based, integrated and policy-relevant analysis of current and emerging energy issues and options. It has been peer-reviewed anonymously by an additional 200 international experts. The GEA assesses the major global challenges for sustainable development and their linkages to energy; the technologies and resources available for providing energy services; future energy systems that address the major challenges; and the policies and other measures that are needed to realize transformational change toward sustainable energy futures. The GEA goes beyond existing studies on energy issues by presenting a comprehensive and integrated analysis of energy chalenges, opportunities and strategies, for developing, industrialized and emerging economies. This volume is a invaluable resource for energy specialists and technologists in all sectors (academia, industry and government) as well as policymakers, development economists and practitioners in international organizations and national governments.

Global Energy Assessment: Toward a Sustainable Future

Low crystalline iron hydroxides such as goethite (alpha-FeOOH) and akaganeite (beta-FeOOH) were synthesized, and the selective adsorption of phosphate ions from phosphate-enriched seawater was examined. The results of the distribution coefficients (K(d)) of oxoanions in mixed anion solutions at pH 8 follow the selectivity order Cl-, NO3-, SO4(2-) << CO3(2-), HPO4(2-) for goethite, and Cl-, CO3(2-) < NO3- < SO4(2) << HPO4(2-) for akaganeite. In seawater, both adsorbents show high selectivity for phosphate ions despite the presence of large amounts of major cations and anions in seawater. The adsorption isotherms fitted better with the Freundlich equation and the maximum uptake of phosphate from phosphate-enriched seawater was 10 mg P/g at an equilibrium phosphate concentration of 0.3 mg P/L on both adsorbents. The phosphate adsorption/desorption cycles show that akaganeite is an excellent adsorbent even after 10 cycles and its chemical stability is good.

Phosphate adsorption on synthetic goethite and akaganeite.

Manganese oxide adsorbent (H1.6Mn1.6O4) was synthesized from precursor Li1.6Mn1.6O4 that was obtained by heating LiMnO2 at 400 °C. LiMnO2 was prepared by two methods:  hydrothermal and reflux. The crystallite size of Li1.6Mn1.6O4 and its delithiated product was slightly higher by the hydrothermal method as compared to the reflux method. The adsorbents prepared by the two methods were compared in terms of physical characteristics and lithium adsorption from seawater. The maximum uptake of lithium from seawater by the adsorbent was 40 mg/g, which is the maximum value among the adsorbents studied to date.

Recovery of Lithium from Seawater Using Manganese Oxide Adsorbent (H1.6Mn1.6O4) Derived from Li1.6Mn1.6O4

Selective adsorption of phosphate from seawater and wastewater by amorphous zirconium hydroxide.

The details of the ion exchange properties of layered H2TiO3, derived from the layered Li2TiO3 precursor upon treatment with HCl solution, with lithium ions in the salt lake brine (collected from Salar de Uyuni, Bolivia) are reported. The lithium adsorption rate is slow, requiring 1 d to attain equilibrium at room temperature. The adsorption of lithium ions by H2TiO3 follows the Langmuir model with an adsorptive capacity of 32.6 mg g−1 (4.7 mmol g−1) at pH 6.5 from the brine containing NaHCO3 (NaHCO3 added to control the pH). The total amount of sodium, potassium, magnesium and calcium adsorbed from the brine was <0.30 mmol g−1. The H2TiO3 was found capable of efficiently adsorbing lithium ions from the brine containing competitive cations such as sodium, potassium, magnesium and calcium in extremely large excess. The results indicate that the selectivity order Li+ ≫ Na+, K+, Mg2+, Ca2+ originates from a size effect. The H2TiO3 can be regenerated and reused for lithium exchange in the brine with an exchange capacity very similar to the original H2TiO3.

Lithium recovery from salt lake brine by H2TiO3

Adsorptive properties of MgMn-3-300 (MgMn-type layered double hydroxide with Mg/Mn mole ratio of 3, calcined at 300 degrees C) for phosphate were investigated in phosphate-enriched seawater with a concentration of 030 mg-P/dm3 It showed the highest phosphate uptake from the seawater among the inorganic adsorbents studied (hydrotalcite, calcined hydrotalcite, activated magnesia, hydrous aluminum oxide, manganese oxide (delta-MnO2)) The phosphate uptake by MgMn-3-300 reached 73 mg-P/g at an adsorbent/solution ratio of 005 g/2 dm3 The analyses of the uptakes of other constituents (Na+, K+, Ca(+, Cl-, and SO(2-)4) of seawater showed that the adsorbent had a markedly high selectivity for the adsorption of phosphate ions Effects of initial phosphate concentration, temperature, pH, and salinity on phosphate uptake were investigated in detail by a batch method The phosphate uptake increased slightly with an increase in the adsorption temperature The adsorption isotherm followed Freundlich's equation with constants of logK(F)=125 and 1/n=065, indicating that it could effectively remove phosphate even from a solution of markedly low phosphate concentration as well as with large numbers of coexisting ions The pH dependence showed a maximum phosphate uptake around pH 85 The pH dependence curve suggested that selective phosphate adsorption progresses mainly by the ion exchange of HPO(2-)4 The study on the effect of salinity suggested the presence of two kinds of adsorption sites in the adsorbent: one nonspecific site with weak interaction and one specific site with strong interaction The effective desorption of phosphate could be achieved using a mixed solution of 5 M NaCl + 01 M NaOH (1 M = 1 mol/dm3), with negligible dissolution of adsorbent The adsorbent had high chemical stability against the adsorption/desorption cycle; it kept a good phosphate uptake even after the repetition of the seventh cycle

Ramesh Chitrakar

Papers

Phosphate adsorption on synthetic goethite and akaganeite.

Recovery of Lithium from Seawater Using Manganese Oxide Adsorbent (H1.6Mn1.6O4) Derived from Li1.6Mn1.6O4

Selective adsorption of phosphate from seawater and wastewater by amorphous zirconium hydroxide.

Lithium recovery from salt lake brine by H2TiO3

Adsorption of phosphate from seawater on calcined MgMn-layered double hydroxides