Competitive Li+ Coordination in Ionogel Electrolytes for Enhanced Li-Ion Transport Kinetics

Developing ionogel electrolytes based on ionic liquid instead of volatile liquid in gel polymer electrolytes is regarded to be effective to diminish safety concerns in terms of overheating and fire. Herein, a zwitterion-based copolymer matrix based on the copolymerization of trimethylolpropane ethoxylate triacrylate (ETPTA) and 2-methacryloyloxyethylphosphorylcholine (MPC, one typical zwitterion) is developed. It is shown that introducing zwitterions into ionogel electrolytes can effectively optimize local lithium-ion (Li+ ) coordination environment to improve Li+ transport kinetics. The interactions between Li+ and bis(trifluoromethanesulfonyl)imide (TFSI- )/MPC lead to the formation of Li+ coordination shell jointly occupied by MPC and TFSI- . Benefiting from the competitive Li+ attraction of TFSI- and MPC, the energy barrier of Li+ desolvation is sharply decreased and thus the room-temperature ionic conductivity can reach a value of 4.4 × 10-4 S cm-1 . Besides, the coulombic interaction between TFSI- and MPC can greatly decrease the reduction stability of TFSI- , boosting in situ derivation of LiF-enriched solid electrolyte interface  layer on lithium metal surface. As expected, the assembled Li||LiFePO4 cells deliver a high reversible discharge capacity of 139 mAh g-1 at 0.5 C and good cycling stability. Besides, the pouch cells exhibit a steady open-circuit voltage and can operate normally under abuse testing (fold, cut), showing its outstanding safety performance.

A photoelectrochemical sensor for Hg2+ detection with enhanced cathodic photocurrent via BiOI/Bi2S3 photoanode of self-sacrifice

Due to the inherent merits of the anodic photoelectrochemical (PEC) sensor, it was widely utilized in the field of analytical chemistry. However, it must be noted that the anodic PEC sensor was susceptible to interference in practical applications. The situation with the cathodic PEC sensor was exactly the opposite. Therefore, this work fabricated a PEC sensor combining photoanode and photocathode that solved the defects of conventional PEC sensors in detecting Hg²⁺. Specifically, Na₂S solution was carefully dropped on the BiOI-modified indium-tin oxide (ITO) to obtain ITO/BiOI/Bi₂S₃ directly by self-sacrifice method and the resulting electrode was used as photoanode. In addition, a sequential modification process was employed to decorate the ITO substrate with Au nanoparticles (Au NPs), Cu₂O, and L-cysteine (L-cys), thereby realizing the fabrication of the photocathode. Moreover, the presence of Au NPs further amplified the photocurrent of the PEC platform. During the detection process, when Hg²⁺ is present it will bind to the L-cys, resulting in an increase in current, thus enabling sensitive detection of Hg²⁺. The proposed PEC platform exhibited good stability and reproducibility, providing a new idea for the detection of other heavy metal ions.

Hydroxyapatite Nanorods Function as Safe and Effective Growth Factors Regulating Neural Differentiation and Neuron Development

Neural stem cell (NSC) transplantation is one of the most promising therapeutic strategies for neurodegenerative diseases. However, the slow spontaneous differentiation of NSCs often hampers their application in neural repair. Although some biological growth factors accelerate the differentiation of NSCs, their high cost, short half-life, and unpredictable behavior in vivo, as well as the complexity of the operation, hinder their clinical use. In this study, it is demonstrated that hydroxyapatite (HAp), the main component of bone, in the form of nanorods, can regulate the neural differentiation of NSCs and maturation of the newly differentiated cells. Culturing NSCs with HAp nanorods leads to the differentiation of NSCs into mature neurons that exhibit well-defined electrophysiological behavior within 5 days. The state of these neurons is much better than when culturing the cells without HAp nanorods, which undergo a 2-week differentiation process. Furthermore, RNA-sequencing data reveal that the neuroactive ligand-receptor interaction pathway is dominant in the enriched differentiated neuronal population. Hence, inorganic growth factors like HAp act as a feasible, effective, safe, and practical tool for regulating the differentiation of NSCs and can potentially be used in the treatment of neurodegenerative diseases.