Recovery of Lithium and Manganese from Scrap LiMn₂O₄ by Slurry Electrolysis

Recycling of lithium and others metals from lithium-ion battery scraps are significant to prevent resource depletion and environmental protection. In this study, slurry electrolysis was employed for the recovery of lithium and manganese from the scrap LiMn2O4 without addition of the chemical reductant or oxidant. The effect of electric current density, acid concentration, pulp density, and MnSO4 concentration on Li and Mn leaching efficiency and electrode current efficiency was investigated. More than 99 and 92% of Li and Mn were leached at 363 K, and the current efficiency of the cathode and anode can reach 77 and 62%, respectively. Phase analysis indicated that pure MnO2 was deposited in 1.0 mol/L H2SO4, and LiMn2O4 cannot be leached into Mn2+ directly. The leaching of Mn2+ from scrap LiMn2O4 involves the steps of Li leaching and MnO2 leaching. Finally, a closed-loop process was proposed for the recovery of high purity of Li2CO3 (99.59 wt %) and MnO2 (92.33 wt %) from scrap LiMn2O4. This process is economically feasible, environmentally friendly, and has great potential for the recovery of other scrap cathode metals

Photodeprotection Reaction Mechanisms of Caged Species Utilizing a Photochromism Function

Acetoxy-1,2,2-tri­(aryl)­ethanone (1) is a novel and visual release-and-report system that contains the photochromic diarylethylene function attached to the photocage dimethoxybenzoin platform. However, the mechanism of 1 cyclization and a subsequent deprotection remains unclear. Here, we use femtosecond and nanosecond transient absorption spectroscopies in combination with density functional theory computations to study the detailed reaction mechanism. The photodeprotection proceeds with competition between pathways initiated by two different configurations of the singlet excited state of 1 (labeled as 11LE and 11CT); the stepwise elimination after cyclization of 11LE constitutes the predominant pathway, whereas the concerted removal of acetic acid after cyclization of 11CT is the minor pathway. These results contribute to a detailed photodeprotection mechanism of 1 and provide new insights into the effect of geometric configurations of intermediates on the photodeprotection pathways. This new information can help in the further development of this type of the photolabile protecting group (PPG) for the protection of biorelevant molecules and in the design of an improved and versatile release-and-report PPG

Solvation-Free Fabrication of PEO/LiTFSI/SiO₂ Composite Electrolyte Membranes with High Ionic Conductivity Based on a Novel Elongational Flow Field

Poly­(ethylene oxide) (PEO)-based composite electrolyte membranes, which silica (SiO2) and lithium bis­(trifluoromethylsulf)­imide (LiTFSI) were introduced into, were successfully prepared by a self-developed eccentric rotor mixer based on an elongational flow field. Characterization results of electrolyte membranes showed that the eccentric rotor mixer can realize the uniform dispersion of LiTFSI in all electrolyte membranes. This produced a high ionic conductivity of the electrolyte membrane. Among all as-prepared membranes, the ionic conductivity of PEO5 exhibited the highest value of 2.96 × 10–4 S·cm–1 at room temperature due to reaching an extremely uniform dispersion of SiO2. After 90 charge–discharge cycles, the Coulomb efficiency of the LPF/PEO5/Li was still close to 100%, and the discharge specific capacity weakly decreased, revealing an extremely good electrochemical performance of PEO5. Therefore, the eccentric rotor mixer provides an effective strategy for facilitating the development of high-efficiency all-solid-state lithium-ion batteries

Apoptosis detected by Hoechst 33342 staining.

<p>Hoechst-positive cells were observed under a fluorescence microscope. Scale bar = 100 μm. (A) Normal cells displayed intact nuclei and adqulis chromatin. Typical morphological features of apoptosis induced by 24-h tachypacing, such as shrunken cells with condensed or fragmented nuclei, are indicated by arrows. (B) Apoptosis was induced by pacing with or without pretreatment with specific inhibitors 2 h prior to 24-h pacing. (C) The percentage of apoptotic cells is expressed as the means ± SD of 3 independent experiments. * * *P < 0.001 versus the control group; ^{# # #} P < 0.001 versus the pacing group.</p

The ER Stress-Mediated Mitochondrial Apoptotic Pathway and MAPKs Modulate Tachypacing-Induced Apoptosis in HL-1 Atrial Myocytes

<div><p>Background and Object</p><p>Cell apoptosis is a contributing factor in the initiation, progression and relapse of atrial fibrillation (AF), a life-threatening illness accompanied with stroke and heart failure. However, the regulatory cascade of apoptosis is intricate and remains unidentified, especially in the setting of AF. The aim of this study was to explore the roles of endoplasmic reticulum (ER) stress, mitochondrial apoptotic pathway (MAP), mitogen-activated protein kinases (MAPKs), and their cross-talking in tachypacing-induced apoptosis.</p><p>Methods and Results</p><p>HL-1 cells were cultured in the presence of tachypacing for 24 h to simulate atrial tachycardia remodeling. Results showed that tachypacing reduced cell viability measured by the cell counting kit-8, dissipated mitochondrial membrane potential detected by JC-1 staining and resulted in approximately 50% apoptosis examined by Hoechst staining and annexin V/propidium iodide staining. In addition, the proteins involved in ER stress, MAP and MAPKs were universally up-regulated or activated via phosphorylation, as confirmed by western blotting; and reversely silencing of ER stress, caspase-3 (the ultimate executor of MAP) and MAPKs with specific inhibitors prior to pacing partially alleviated apoptosis. An inhibitor of ER stress was applied to further investigate the responses of mitochondria and MAPKs to ER stress, and results indicated that suppression of ER stress comprehensively but incompletely attenuated the activation of MAP and MAPKs aroused by tachypacing, with the exception of ERK1/2, one branch of MAPKs.</p><p>Conclusions</p><p>Our study suggested tachypacing-induced apoptosis is regulated by ER stress-mediated MAP and MAPKs. Thus, the above three components are all promising anti-apoptotic targets in AF patients and ER stress appears to play a dominant role due to its comprehensive effects.</p></div

Mitochondrial membrane potential assessed by JC-1 dye.

<p>Cells were treated as labeled, stained with JC-1 dye and then observed under a fluorescence microscope. Scale bar = 400μm. Red fluorescence represents JC-1 aggregates formed in normal cells with high △ψm, whereas green fluorescence represents JC-1 monomers in cells with low △ψm.</p

The impact of ER stress on the phosphorylation of MAPKs in pacing-induced apoptosis.

<p>HL-1 cells were treated as labeled. The protein levels of phosphorylated JNK (A), P38 (B) and ERK (C) were normalized to total JNK, P38 and ERK. The quantitative analysis of relative protein level is expressed as the means ± SD of 3 independent experiments. *P < 0.05 and * * P < 0.01 versus the control group; ^# P < 0.05 and ^{# #} P < 0.01 versus the pacing group.</p

Selective Integrating Molecular Catalytic Units into Bipyridine-Based Covalent Organic Frameworks for Specific Photocatalytic Fuel Production

Molecular metal compounds have demonstrated excellent catalytic activity and product selectivity in the H2 evolution reaction (HER) and the CO2 reduction reaction (CO2RR). The heterogenization of molecular catalysts is regarded as an effective approach to improve their applicability. In this work, the molecular catalytic units [Cp*Ir(Bpy)Cl]+ and [Ru(Bpy)(CO)2Cl2] are constructed in situ on the bipyridine sites of the covalent organic framework for photocatalytic HER and CO2RR, respectively. Inheriting the impressive performance of molecular catalysts, the functionalized TpBpy–M exhibits excellent catalytic activity and product selectivity. Under visible light irradiation, the H2 production rate of TpBpy–Ir is about 760 μmol g–1 h–1, which is 6.7 times higher than that of TpBpy without built-in catalytic sites. Also, the HCOOH production rate of TpBpy–Ru is 271 μmol g–1 h–1, with an impressive selectivity of 88%. Control experiments validated that this improvement is attributed to the incorporation of molecular catalytic units into the framework. Photoluminescence spectroscopy measurements and theoretical calculation consistently demonstrate that, under illumination, the photosensitizer [Ru(Bpy)3]Cl2 is excited and transfers electrons to the catalytic sites in TpBpy–M, which then catalyzes the reduction of H+ and CO2

Effects of tachypacing on cell viability.

<p>HL-1 cells were subjected to tachypacing for 1, 6, 12 and 24 h. Cell viability was measured with CCK-8 assay and the results are presented as the means ± SD of 3 independent experiments. *P < 0.05; * * *P < 0.001 versus the control group.</p