Sodium-ion batteries are regarded as one of the most promising energy storage systems, but the choice of anode material is still facing great challenges. Biomass carbon materials were explored for their low cost and wide range of sources. Here, a hard carbon material with a "honeycomb" structure using pine pollen (PP) as a precursor was successfully prepared and applied as an anode. The initial discharge capacity can reach 370 mA h g −1 at a current density of 0.1 A g −1 . After cycling 200 times, the reversible capacity also stabled at 203.3 mA h g −1 with the retention rate of 98%. We further studied the sodium storage mechanism by different methods, especially the Na + diffusivity coefficient (D Na + ) calculated by galvanostatic intermittent titration technique, which was more accurate. Interestingly, the trend of D Na + coincides with cyclic voltammetry curves. Carbonized PP exhibited excellent electrochemical properties because of its three-dimensional structure and larger layer spacing (∼0.41 nm), which reduces the resistance of sodium ions to intercalation and deintercalation.

Hard carbon materials are characterized by having rich resources, simple processing technology, and low cost, and they are promising as one of the anode electrodes for commercial applications of sodium-/potassium-ion batteries.Simultaneously, exploring the alkali metal ion storage mechanism is particularly important for designing high-performance electrode materials. However, the structure of hard carbon is more complex, and the description of energy storage behavior is quite controversial. In this study, the Magnolia grandiflora Lima leaf is used as a precursor, combined with simple pyrolysis and impurity removal processes, to obtain biomass-derived hard carbon material (carbonized Magnolia grandiflora Lima leaf [CMGL]). When it is used as an anode for sodium-ion batteries, it exhibits a high specific capacity of 315 mAh/g, and the capacity retention rate is 90.0% after 100 cycles. For potassium-ion batteries, the charge specific capacity is 263.5 mAh/g, with a capacity retention rate of 85.5% at the same cycling. Furthermore, different electrochemical analysis methods and microstructure characterization techniques were used to further elucidate the sodium/potassium storage mechanism of the material. All the results indicate that the high potential slope region represents the adsorption/desorption characteristics on the surface active sites, whereas the low-potential quasiplateau region belongs to the ion insertion/extraction in the graphitic microcrystallites interlayer. It is noteworthy that potassium ion is randomly

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On-chip micro-supercapacitors (MSCs) have attracted great attention recently. However, the performance of MSCs is usually unsatisfactory because of the unreasonable pore structure. The construction of a three-dimensional (3D) interconnected porous carbon-based MSC by controllable activation is proposed. The porous monolithic carbon microelectrode activated by ZnO nanowires provides electron/ion bicontinuous conduction path. The fabricated MSC with this microelectrode rendered a high areal specific capacitance of 10.01 mF cm–2, 6 times higher than that of pure pyrolyzed carbon-based MSC, 1.6–5 times higher than that of the MSC with porous carbon activated by ZnO nanoparticles because of its cross-linking macropore–mesopore–micropore structure and considerable areal atomic ratio. The optimization mechanism of the hierarchical channel pore for the electrochemical performance of MSCs is investigated in detail. Four kinds of electrolytes, including H2SO4, redox additive KI/H2SO4, LiCl, and LiTFSi, are employed for constructing MSCs. The voltage window of water in a salt electrolyte assembled LiTFSi-MSC is expanded to 2.5 V. The energy density of LiTFSi-MSC is 6 times higher than that of H2SO4-MSC, which can drive light-emitting diodes without serial or parallel connection. This high-performance 3D interconnected porous carbon-based MSC shows a great potential in applications for large-scale integration of micro-/nanodevices.

The stem cell leukemia (SCL or tal-1) gene was initially identified as a translocation partner in a leukemia that possessed both lymphoid and myeloid differentiation potential. Mice that lacked SCL expression showed a complete block in hematopoiesis; thus, SCL was associated with hematopoietic stem cell (HSC) function. More recent studies show a role for SCL in murine erythroid differentiation. However, the expression pattern and the role of SCL during early stages of human hematopoietic differentiation are less clear. In this study we chart the pattern of human SCL expression from HSCs, through developmentally sequential populations of lymphoid and myeloid progenitors to mature cells of the hematopoietic lineages. Using recently defined surface immunophenotypes, we fluorescenceactivated cell-sorted (FACS) highly purified populations of primary human hematopoietic progenitors for reverse transcription-polymerase chain reaction (RT-PCR) analysis of SCL expression. Our data show that SCL mRNA is easily detectable in all hematopoietic populations with erythroid potential, including HSCs, multipotential progenitors, common myeloid progenitors, megakaryocyte/erythrocyte progenitors, and nucleated erythroid lineage cells. SCL mRNA expression was present but rapidly downregulated in the common lymphoid progenitor and granulocyte/monocyte progenitor populations that lack erythroid potential. SCL expression was undetectable in immature cells of nonerythroid lineages, including pro-B cells, early thymic progenitors, and myeloid precursors expressing the M-CSF receptor. SCL expression was also absent from all mature cells of the nonerythroid lineages. Although low levels of SCL were detected in lymphoid-and myeloid-restricted progenitors, our studies show that abundant SCL expression is normally tightly linked with erythroid differentiation potential. Stem Cells 2005;23:852-860