Developing high-performance batteries relies on material breakthroughs. During the past few years, various in situ characterization tools have been developed and have become indispensible in studying and the eventual optimization of battery materials. However, soft X-ray spectroscopy, one of the most sensitive probes of electronic states, has been mainly limited to ex situ experiments for battery research. Here we achieve in situ and operando soft X-ray absorption spectroscopy of lithium-ion battery cathodes. Taking advantage of the elemental, chemical and surface sensitivities of soft X-rays, we discover distinct lithium-ion and electron dynamics in Li(Co_1/3Ni_1/3Mn_1/3)O₂ and LiFePO₄ cathodes in polymer electrolytes. The contrast between the two systems and the relaxation effect in LiFePO₄ is attributed to a phase transformation mechanism, and the mesoscale morphology and charge conductivity of the electrodes. These discoveries demonstrate feasibility and power of in situ soft X-ray spectroscopy for studying integrated and dynamic effects in batteries.

A novel magnetic Pb(II) ion-imprinted polymer was prepared via surface ion-imprinting technique by using magnetic Fe₃O₄@SiO₂ microspheres as supporter, Pb(II) as template ion, methacrylic acid and salicylaldoxime as monomers, and ethylene glycol dimethacrylate as crosslinker. The product was characterized by FT-IR, VSM, XRD, and SEM. The adsorption experiments showed that the imprinted polymer was employed successfully in comparison with non-imprinted polymer. When the temperature was in a range of 277 K to 291 K the maximum adsorption was about 81.83 mg/g with an optimal pH 6.0. Its relative selectivity coefficient values of Pb(II)/Cu(II), Pb(II)/Zn(II), and Pb(II)/Cd(II) were 2.60, 6.38, and 7.89 times greater than the ones of the magnetic non-imprinted polymer. The Langmuir adsorption model was more favorable for M-IIP than Freundlich or Temkin adsorption models. The Scatchard analysis suggested that M-IIP was processed with two kinds of binding sites with different affinity. Thermodynamic experiment showed that the adsorption was a spontaneous and endothermic process for Pb(II). The mechanism for Pb(II) adsorption on the imprinted polymer was also investigated.

Three‐dimensional porous graphene (3D‐PG) has attracted much attention due to its excellent electrochemical performance. Chemical reduction is one of common methods for preparing porous graphene. In order to develop a green and facile method for preparing three‐dimensional porous graphene, in this paper, 3D‐PG was fabricated by reduction of graphene oxide (GO) with ascorbic acid (AA) as reductant in hydrothermal condition based on non‐toxic, non‐flammable and mild reducing performance of ascorbic acid. It was found that the size and distribution of pores could be controlled by the reduction time and the concentration of AA in the solution. The pore sizes in R0, R1 and R2 were in the range of 0.5–1 μm, 1–1.5 μm, and 1.5–3 μm, respectively. It was found that the average pore size and volume increased along with the amount of reductants. Under optimal conditions – a reaction time of 20 h and a ratio of GO to AA=1 : 1 – the CV area of the so‐obtained sample R1‐20 at 100 mV was 0.06 and the specific capacitance of the 3D‐PG electrode reaches 153.5 F ⋅ g⁻¹, which is suitable for use in supercapacitors.