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Additives are very important to enhance the performance of lead-acid batteries. In this paper, formic acid is used as an electrolyte additive to study its effect on battery performance. The results show formic acid has an opposite effect on the electrochemical properties of pure lead at positive and negative potentials. Besides, formic acid can make more active materials participate in the reaction, increase the rate of conversion of lead to lead sulfate, and reduce the internal resistance of the battery. Moreover, formic acid batteries exhibit better rate performance and higher specific discharge capacity than the blank. Especially, when the 0.5 wt% formic acid is used, the discharge capacity can reach 87.0 mAh g −1 when it is discharged at 400 mA g −1 . After 1200 cycles of charge and discharge at a current density of 100 mA g −1 , the specific discharge capacity is still 68.1 mAh g −1 , which is 1.42 times higher than that of blank cells.

Agglomerated nanorods of lead phosphate have been synthesized from the reaction of lead acetate prepared from waste lead paste and Na 2 HPO 4 , which is used as an additive for the PbSO 4 -negative electrode of a lead-acid cell. It has been found that lead phosphate can be all converted to lead sulfate in 36 wt.% sulfuric acid electrolyte and generate phosphoric acid, and the negative active material containing 1 wt.% lead phosphate discharges a capacity of 111 mAh g −1 at 100 mA g −1 till 1.75 V; it still discharges 78 mAh g −1 after 1200 cycles, which is 10.1% higher than the blank PbSO 4 electrode. It is believed that phosphoric acid could remove the non-conductive oxide on the lead alloy grid; thus, a better conductive network could be built. Also, phosphoric acid is adsorbed on PbSO 4 particles, which can improve the reversibility of the electrode and diminish the shedding of PbSO 4 .

Lead formate (LF) has been successfully prepared from compounds in spent lead-acid batteries by a simple and low-cost method. The irregular sheets of LF pile up to form agglomerated particles. When it is used as an additive in the negative electrode, it makes the electrode perform better and be able to discharge a capacity of 107 mAh g −1 at 100 mA g −1 to 1.75 V; it still discharges 86.5 mAh g −1 after 1200 cycles. EIS shows that the electrode has lower resistance and higher ion diffusion rates than the one without LF. The reason could be that LF produces formic acid when it meets sulfuric acid, and the formic acid could clear up the oxide on lead alloy grid as well as basic lead sulfate in the electrode, thus making the conduction network grow better.

The radicals and high temperatures generated by the Oxyhydrogen flame induce new reactions. This paper reports on the treatment of saturated chloride solutions with Oxyhydrogen flame. The results show that the oxyhydrogen flame can promote the hydrolysis definitely, including strong acid and strong alkali salts like NaCl and KCl. The extent and product of the hydrolysis depends on the Lewis acidity and hardness of the metal ions in the chlorides. The higher is the Lewis acidity of metal ions, and the higher is the extent of hydrolysis, thus the efficiency of oxyhydrogen flame ( E H ) of AlCl 3 is the highest, up to 2.95%, as Al 3+ is the strongest Lewis acid. Soft metals tend to produce basic chloride, and the harder ones prefer the oxides, carbonates or hydroxides. Through the exploration of this paper the authors believe that the hydroxide flame can be a universal method for treating any kind of chemical waste. Graphical Abstract

Elemental tellurium, conventionally recognized as a narrow bandgap semiconductor, has recently aroused research interests for exploiting Weyl physics. Chirality is a unique feature of Weyl cones and can support helicity-dependent photocurrent generation, known as circular photogalvanic effect. Here, we report circular photogalvanic effect with opposite signs at two different mid-infrared wavelengths which provides evidence of Weyl-related optical responses. These two different wavelengths correspond to two critical transitions relating to the bands of different Weyl cones and the sign of circular photogalvanic effect is determined by the chirality selection rules within certain Weyl cone and between two different Weyl cones. Further experimental evidences confirm the observed response is an intrinsic second-order process. With flexibly tunable bandgap and Fermi level, tellurium is established as an ideal semiconducting material to manipulate and explore chirality-related Weyl physics in both conduction and valence bands. These results are also directly applicable to helicity-sensitive optoelectronics devices. Materials with Weyl cones and band gaps coexisting are desired due to their combination of Weyl cones and the tunable and controllable nature of semiconductor. Here, the authors find Weyl-related band structures and semiconducting gap of tellurium.