Multiscale strain alleviation of Ni-rich cathode guided by in situ environmental transmission electron microscopy during the solid-state synthesis

Ni-rich layered oxides are one of the most promising cathode materials for Li-ion batteries due to their high energy density.However,the chemomechanical breakdown and capacity degradation associated with the anisotropic lattice evolution during lithiation/delithiation hinders its practical application.Herein,by utilizing the in situ environmental transmission electron microscopy(ETEM),we provide a real time nanoscale characterization of high temperature solid-state synthesis of LiNi_(0.8)CO_(0.1)Mn_(0.1)O_(2)(NCM811) cathode,and unprecedentedly reveal the strain/stress formation and morphological evolution mechanism of primary/second ary particles,as well as their influence on electrochemical performance.We show that stress inhomogeneity during solid-state synthesis will lead to both primary/secondary particle pulverization and new grain boundary initiation,which are detrimental to cathode cycling stability and rate performance.Aiming to alleviate this multiscale strain during solid-state synthesis,we introduced a calcination scheme that effectively relieves the stress during the synthesis,thus mitigating the primary/secondary particle crack and the detrimental grain boundaries formation,which in turn improves the cathode structural integrity and Li-ion transport kinetics for long-life and high-rate electrochemical performance.This work remarkably advances the fundamental understanding on mechanochemical properties of transition metal oxide cathode with solid-state synthesis and provides a unified guide for optimization the Ni-rich oxide cathode.

Influence of High Temperature on the Expression of Arabidopsis Heat Shock Transcription Factor AtHsfA1a

[ Objective] This study ~med to investigate the influence of high temperature on the expression of heat shock transcription factor AtHsfAla in different genotypes of Arabidopsis. [ Method ] Arabidopsis plants overexpressing heat shock transcription factor AtHsfA1 a were used as experimental materials and treated un- der high temperature at 39℃ for 1 rain and 5 min; total RNA of AtI-IsfAla was extracted, and the reverse transcription and amplification were conducted using RT- PCR technology, the amplification products were detected by electrophoresis. [ Result ] The expression levels of AtHsfA1 a in Arabidopsis plants overexpressing heat shock transcription factor AtHsfAla at high temperature and room temperature were higher than wild-type Arabidopsis; the expression levels of AtHsfAla in both wild-type Arab/dops/s and transgenic Arabidopsls plants overexpressing heat shock transcription factor AtHsfAla at high temperature of 39 ~C were higher than that at room temperature of 25 ~C, but the expression levels of AtHsfAla in wild-type Arab/dops/s and transgenic Arab/dops/s plants overexpressing heat shock transcription factor AtHsfAla varied little after high temperature treatment at 39 ~C for 1 rain or 5 rain. [ Conclusion] The expression of AtHsfAla is induced rapidly by high tem- perature, thus regulating the expression of early adversity-resistant genes. This study will lay the foundation demonstrating the mechanism of Arabidopsis heat shock transcription factor AtHsfAla.

A revisiting of transition metal phosphide(Cu_(3)P and FeP)nanozymes for two sugar-related reactions

Transition metal phosphides(TMPs)are essential catalysts for some general catalytic reactions.However,their potentials for biological catalysis have seldom been explored.Herein,we investigated the enzyme-like properties of four TMPs(FeP,CoP,Ni_(2)P,and Cu_(3)P)towards two sugar-related reactions.Among the four TMPs,Cu_(3)P nanoparticles(NPs)efficiently catalyzed the hydrolysis of glycosidic bonds as glycoside hydrolase mimics,and FeP NPs possessed both glucose oxidase-like(GOx-like)and peroxidase-like activities,which combined into a cascade reaction for glucose’s simple and one-step colorimetric biosensor without GOx.Cu_(3)P and FeP NPs with distinctive enzyme-like activities have shown unique biological catalysis potentials for further applications with an attractive and challenging goal of developing nanomaterials to mimic natural enzymes,which encourages more efforts to reveal TMP’s capabilities towards biocatalysis.