Sodium?ion batteries are considered a promising alternative to lithium?ion and lead?acid batteries, offering a balance between performance and cost?effectiveness for applications requiring moderate energy density and low cost. Hard carbon stands out as the most promising anode material for sodium?ion batteries, with the majority of scholars attributing its sodium storage capacity primarily to its porous structure. However, characterization techniques for this porous structure are currently very limited. This hinders in?depth analysis of the hard carbon pore structure and makes it more difficult to design performance enhancement strategies. This review provides an overview of current methods for characterizing the pore structure of hard carbon, including transmission electron microscopy, gas adsorption, X?ray small angle scattering, and helium true density testing. The combined use of these methods helps accurately characterize the pore structure of hard carbon and provides research ideas and technical support for the design of high?performance hard carbon anodes.

In recent years, many oil wells in Mahu oil fields have experienced scaling on the pipe wall, which leads to wellbore blockage and seriously affects the production effect. In this paper, the structure and composition of scale in Mahu oilfield were studied, and the mechanism of scale formation was investigated by using OLI?ScaleChem simulation method and the interaction experiments between fluid and rock matrix. The results show that the main fouling is CaCO₃, and the deeper the well is, the larger the amount of scale is. In addition, the wellbore temperature, pressure and pH of the fluid all have certain influence on scaling. According to the results of fluid rock reaction, it is inferred that CaCO₃ scale is the reaction product of highly mineralized fluid and calcium?rich minerals under the condition of acidic well fluid, and forms into balls under the action of polymer, resulting in hole and wellbore plugging. The results of the study are of great significance in guiding the proposal of subsequent scaling prevention and treatment measures in the oilfield.