We report the electrochemical intercalation−extraction of aluminum (Al) in the layered TiS 2 and spinel-based cubic Cu 0.31 Ti 2 S 4 as the potential cathode materials for rechargeable Al-ion batteries. The electrochemical characterizations demonstrate the feasibility of reversible Al intercalation in both titanium sulfides with layered TiS 2 showing better properties. The crystallographic study sheds light on the possible Al intercalation sites in the titanium sulfides, while the results from galvanostatic intermittent titration indicate that the low Al 3+ diffusion coefficients in the sulfide crystal structures are the primary obstacle to facile Al intercalation−extraction.

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slags at the steelmaking endpoint during an 80-ton top-bottom combined blown converter steelmaking process has been developed based on the ion and molecule coexistence theory (IMCT). The phosphate capacity has a close relationship with the phosphate capacity index, whereas the logarithm of phosphate capacity is 12.724 greater than that of phosphate capacity index at 1873 K (1600°C). The developed phosphate capacity prediction model can be also used to predict the phosphate capacity index with reliable accuracy compared with the measured and the predicted phosphate capacity index of the slags by other models in literatures. The results from the IMCT phosphate capacity prediction model show that the comprehensive effects of iron oxides and basic components control the dephosphorization reaction with an optimal ratio of (pct FeO)/(pct Fe 2 O 3 ) as 0.62. The determined contribution ratio of Fe t O, CaO + Fe t O, MgO + Fe t O, and MnO + Fe t O to the phosphate capacity or phosphate capacity index of the slags is approximately 0.0 pct, 99.996 pct, 0.0 pct, and 0.0 pct, respectively. The generated 2CaOAEP 2 O 5 , 3CaOAEP 2 O 5 , and 4CaOAEP 2 O 5 as products of dephosphorization reactions accounts for 0.016 pct, 96.01 pct, and 3.97 pct of the phosphate capacity or phosphate capacity index of the slags, respectively.

An essential requirement for electrolytes in rechargeable magnesium-ion (Mg-ion) batteries is to enable Mg plating−stripping with low overpotential and high Coulombic efficiency. To date, the influence of the Mg/ electrolyte interphase on plating and stripping behaviors is still not well understood. In this study, we investigate the Mg/ electrolyte interphase from electrolytes based on two Mg salts with weakly coordinating anions: magnesium monocarborane ( M g ( C B 1 1 H 1 2 ) 2 ) a n d m a g n e s i u m b i s -(trifluoromethanesulfonyl)imide (Mg(TFSI) 2 ). Cyclic voltammetry and chronopotentiometry of Mg plating−stripping demonstrate significantly lower overpotential in the Mg-(CB 11 H 12 ) 2 electrolyte than in Mg(TFSI) 2 under the same condition. Surface characterizations including X-ray photoelectron spectroscopy and scanning electron microscopy clearly demonstrate the superior chemical and electrochemical stability of the Mg(CB 11 H 12 ) 2 electrolyte at the Mg surface without noticeable interphase formation. On the other hand, characterizations of the Mg/electrolyte interface in the Mg(TFSI) 2 electrolyte indicate the formation of magnesium oxide, magnesium sulfide, and magnesium fluoride as the interfacial compounds resulting from the decomposition of TFSI − anions because of both chemical reduction by Mg and cathodic reduction during Mg deposition.

The self‐standing electrode nanomaterials with highly effective bifunctional electrocatalysis for oxygen reduction and evolution reactions (ORR/OER) are important for practical applications in metal–air batteries. Herein, a defect‐enriched and pyridinic‐N (PN) dominated bifunctional electrocatalyst with novel core–shell architecture (DN‐CP@G) is successfully fabricated by in situ exfoliating graphene from carbon paper followed by high temperature ammonia treatment. Benefitting from its strongly coupled core–shell structure, abundant defective sites and high‐content PN dopants, the DN‐CP@G displays an excellent electrocatalytic (ORR and OER) activity and stability in alkaline media, which are comparable to commercial Pt/C and Ir/C catalysts. The experiment, and theoretical calculations demonstrate that the electrocatalytic activities of carbon materials strongly depend on their defective sites and PN dopants. By directly using DN‐CP@G as a self‐standing electrode, the assembled zinc–air battery demonstrates a high discharge performance and outstanding long‐term cycle stability with at least 250 cycles, which is much superior to the mixed Pt/C and Ir/C electrodes. Remarkably, the DN‐CP@G based all‐solid‐state battery also reveals a good discharge and cycle performance. A facile and cost‐efficient approach to prepare highly effective bifunctional self‐standing electrode is provided by in situ generation of active sites on carbon support for metal–air batteries.

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A thermodynamic model for calculating the mass action concentrations of structural units in CaO-SiO 2 -MgO-FeO-MnO-Al 2 O 3 -CaF 2 slags, i.e., the IMCT-N i model, has been developed based on the ion and molecule coexistence theory (IMCT). The calculated comprehensive mass action concentration of iron oxides N Fe t O has been compared with the reported activity of iron oxide a Fe t O in 14 FeO-containing slag systems from literatures. The good agreement between the calculated N Fe t O and reported a Fe t O indicates that the developed IMCT-N i model can be successfully applied to predict the activity of iron oxide a Fe t O as well as the slag oxidation ability of CaO-FeO (s1), SiO 2 -FeO (s2), CaO-SiO 2 -FeO (s3), CaO-FeO-Al 2 O 3 (s4), SiO 2 -MgO-FeO (s5), SiO 2 -FeO-Al 2 O 3 (s6), CaO-SiO 2 -FeO-Al 2 O 3 (s7), CaO-SiO 2 -MgO-FeO-Al 2 O 3 (s8), SiO 2 -FeO-MnO (s9), SiO 2 -FeO-MnO-Al 2 O 3 (s10), FeO-MnO (s11), FeO-MnO-Al 2 O 3 (s12), CaO-FeO-CaF 2 (s13), and CaO-SiO 2 -FeO-CaF 2 slags (s14) in a temperature range of 1473-1973 K.

Sodium- and potassium-ion (Na-/K-ion) hybrid capacitors are promising electrochemical energy storage systems that are more cost-effective than corresponding lithium-based alternatives. Their hybrid configuration integrates a battery-type anode and a capacitor-type cathode and affords high energy density, high power density, and good cycling stability. However, the primary issue encountered in Na-/K-ion hybrid capacitors is a lack of reliable anodes because of the sluggish reaction kinetics of large Na-/K-ions. In recent years, significant advancements have been achieved in carbonaceous anodes because of their high Na-/K-ion storage feasibility, natural abundance, low cost, and non-toxicity. This review encompasses the fundamental electrochemical principles of Na-/K-ion hybrid capacitors and provides insights into the intimate structure–performance relationship of carbonaceous anodes. The existing challenges and alternative strategies for improving the electrochemical performance of the carbonaceous anodes are emphasized. Finally, future prospects and possible directions for further improving carbonaceous anodes for Na-/K-ion hybrid capacitors are presented.