A low-cost chloroaluminate electrolyte combining high ionic conductivity with suppressed active-material dissolution is desirable for Al–organic batteries. In this study, a toluene-containing mixed alkylamine hydrochloride–AlCl 3 electrolyte, denoted Tol–MACl–AlCl 3 , was developed for Al || anthraquinone (AQ) batteries. Toluene addition effectively reduced the viscosity of MACl–AlCl 3 and increased its ionic conductivity. The optimized Tol–MACl–AlCl 3 electrolyte exhibited an ionic conductivity of 21.6 mS cm −1 at 28 °C, higher than that of the conventional EMImCl–AlCl 3 electrolyte, while its estimated material cost was approximately one-tenth that of EMImCl–AlCl 3 . Cyclic voltammetry and galvanostatic electrodeposition analyses confirmed the occurrence of reversible Al plating and stripping in the toluene-containing electrolyte. In addition, AQ displayed lower saturated solubility in the MACl-based and toluene-containing electrolytes than in EMImCl–AlCl 3 , indicating that optimized electrolyte compositions can help suppress dissolution of the organic cathode material. When Tol–MACl–AlCl 3 was used as the electrolyte, the Al || AQ cell delivered an initial discharge capacity of 189 mAh g −1 and retained 122 mAh g −1 after 100 cycles at 100 mA g −1 , markedly outperforming the conventional Al | EMImCl–AlCl 3 | AQ cell. These results demonstrate that Tol–MACl–AlCl 3 improves Al || AQ cell performance through both enhanced ion transport and reduced AQ dissolution, positioning electrolyte optimization as an effective strategy for developing low-cost Al–organic batteries.
Manganese-based oxides are recognized as promising cathode materials for aqueous zinc-ion batteries (AZIBs), owing to their high operating voltage, desirable specific capacity, and abundant elemental reserves. However, sluggish electrochemical reaction kinetics and severe structural degradation of single-phase manganese oxides during long-term charge-discharge cycles significantly impair their cycling stability and rate capability, impeding their large-scale industrial application. In this work, a MnO 2 /Mn 3 O 4 heterostructured composite cathode was successfully synthesized via a facile in-situ electrodeposition method. The unique composition and heterostructure endow the MnO 2 /Mn 3 O 4 composite with abundant active sites, enhanced electrical conductivity, and excellent structural stability. Benefiting from these advantages, the MnO 2 /Mn 3 O 4 composite cathode delivers a high initial specific discharge capacity of 384 mAh g −1 at 0.1 A g −1 , outstanding rate performance with a reversible capacity of 197 mAh g −1 at 2 A g −1 , and ultra-long cycling stability with 95.4% capacity retention after 5000 cycles, which is substantially superior to that of pure MnO 2 and pure Mn 3 O 4 control samples. This work demonstrates a facile and efficient strategy for the design and fabrication of high-performance multiphase manganese-based composite cathodes for next-generation AZIBs.
Oxalic acid and oil co-occur in metal-finishing, descaling and tannery effluents, yet their simultaneous removal by electrocoagulation (EC) has, to our knowledge, not been reported. EC was performed on a synthetic wastewater in a cell using a vertical aluminum serpentine-tube anode (two perpendicular arrays, designed to double as a potential heat exchanger) between two screen cathodes. Effects of pH (2–9), NaCl (1–4 wt%), current density (10.1–36.29 mA/cm 2 ), initial concentrations (oil 250–2000 ppm; oxalic acid 500–5000 ppm), temperature (25–45 °C) and stirring (0–1500 rpm) were examined over 60 min. Under the best conditions tested (pH 7, 2 wt% NaCl, 25 °C, 36.29 mA/cm 2 ; 250 ppm oil, 500 ppm oxalic acid), removal reached 98% and 60%, respectively. Oil removal saturated above ~20 mA/cm 2 , whereas oxalic acid removal rose steadily but was limited by soluble Al–oxalate complexes. Heating to 45 °C lowered oil removal (96→74%) but slightly raised oxalic acid removal (32→40%); stirring had little effect. Specific energy consumption rose with current density (oil: ~6–30 kWh/kg) and fell with pollutant concentration (oxalic acid: 82–12 kWh/kg). Control experiments revealed slight negative effect of oxalic acid on oil removal but synergy for oxalic acid in presence of oil. Kinetic analysis confirmed pseudo-first-order removal for both pollutants. The results are consistent with a competition between coagulation and Al–oxalate complexation and support EC as pretreatment for concentrated oxalic acid–oil wastewaters.
