Lithium-ion batteries (LIBs), used for energy supply and storage equipment, have been widely applied in consumer electronics, electric vehicles, and energy storage systems. However, the urgent demand for high energy density batteries and the shortage of lithium resources is driving scientists to develop high-performance materials and find alternatives. Low-volume expansion carbon material is the ideal choice of anode material. However, the low specific capacity has gradually become the shortcoming for the development of LIBs and thus developing new carbon material with high specific capacity is urgently needed. In addition, developing alternatives of LIBs, such as sodium ion batteries and potassium-ion batteries, also puts forward demands for new types of carbon materials. As is well-known, the design of high-performance electrodes requires a deep understanding on the working mechanism and the structural evolution of active materials. On this issue, ex-situ techniques have been widely applied to investigate the electrode materials under special working conditions, and provide a lot of information. Unfortunately, these observed phenomena are difficult to reflect the reaction under real working conditions and some important short-lived intermediate products cannot be captured, leading to an incomplete understanding of the working mechanism. In-situ techniques can observe the changes of active materials in operando during the charge/discharge processes, providing the concrete process of solid electrolyte formation, ions intercalation mechanism, structural evolutions, etc. Herein, this review aims to provide an overview on the characters of carbon materials in alkali ion batteries and the role of in-situ techniques in developing carbon materials.

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o-Phthalaldehyde-beta-mercaptoethanol (OPAME) as a fluorogenic reagent has been found wide applications in the detection of amino acids based on its reaction with primary amino groups. In this contribution, we report our new findings concerning the reactions of OPAME with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), respectively. It has been found that ssDNA can react with OPAME easily as a result of giving rise to strong fluorescence emissions, while dsDNA, prepared by hybridizing ssDNA with its complementary target prior to the reaction, displays inert chemical activity and gives out weak fluorescence emission. Mechanism investigations have shown that the reaction activity between OPAME and DNA depends on the amino groups that are related to the conformation of uncoiled and exposed extent of DNA structure, and thus the inert chemical activity of dsDNA results from screening of the dsDNA bases in the interior of the double strands. Therefore, we could design a way to detect conformation change of DNA with OPAME and further develop a novel, simple label-free sequence detection method for complementary and single-base mismatched ssDNA in the hybridization of DNA.

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