One great challenge in the development of lithium ion batteries is to simultaneously achieve high power and large energy capacity at fast charge and discharge rates for several minutes to seconds. Here we show that nitrogen- or boron-doped graphene can be used as a promising anode for high-power and high-energy lithium ion batteries under high-rate charge and discharge conditions. The doped graphene shows a high reversible capacity of >1040 mAh g(-1) at a low rate of 50 mA g(-1). More importantly, it can be quickly charged and discharged in a very short time of 1 h to several tens of seconds together with high-rate capability and excellent long-term cyclability. For example, a very high capacity of ∼199 and 235 mAh g(-1) was obtained for the N-doped graphene and B-doped graphene at 25 A g(-1) (about 30 s to full charge). We believe that the unique two-dimensional structure, disordered surface morphology, heteroatomic defects, better electrode/electrolyte wettability, increased intersheet distance, improved electrical conductivity, and thermal stability of the doped graphene are beneficial to rapid surface Li(+) absorption and ultrafast Li(+) diffusion and electron transport, and thus make the doped materials superior to those of pristine chemically derived graphene and other carbonaceous materials.
Superconductivity in the cuprate superconductors and the Fe-based superconductors is realized by doping the parent compound with charge carriers, or by application of high pressure, to suppress the antiferromagnetic state. Such a rich phase diagram is important in understanding superconductivity mechanism and other physics in the Cu-and Fe-based high temperature superconductors.In this paper, we report a phase diagram in the single-layer FeSe films grown on SrTiO 3 substrate by an annealing procedure to tune the charge carrier concentration over a wide range. A dramatic change of the band structure and Fermi surface is observed, with two distinct phases identified that are competing during the annealing process. Superconductivity with a record high transition temperature (T c ) at 65±5 K is realized by optimizing the annealing process. The wide tunability of the system across different phases, and its high-T c , make the single-layer FeSe film ideal not only to investigate the superconductivity physics and mechanism, but also to study novel quantum phenomena and for potential applications.
Cryptochrome 1 (CRY1) is a blue light receptor that mediates primarily blue-light inhibition of hypocotyl elongation. Very little is known of the mechanisms by which CRY1 affects growth. Blue light and temperature are two key environmental signals that profoundly affect plant growth and development, but how these two abiotic factors integrate remains largely unknown. Here, we show that blue light represses high temperature-mediated hypocotyl elongation via CRY1. Furthermore, CRY1 interacts directly with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) in a blue lightdependent manner to repress the transcription activity of PIF4. CRY1 represses auxin biosynthesis in response to elevated temperature through PIF4. Our results indicate that CRY1 signal by modulating PIF4 activity, and that multiple plant photoreceptors [CRY1 and PHYTOCHROME B (PHYB)] and ambient temperature can mediate morphological responses through the same signaling component-PIF4.ryptochromes are photolyase-like blue-light receptors first discovered in Arabidopsis and later found in all major evolutionary lineages (1-4). Arabidopsis cryptochrome 1 (CRY1) and cryptochrome 2 (CRY2) mediate primarily blue-light inhibition of hypocotyl elongation (5) and photoperiodic control of floral initiation (6) via modulation of gene expression. For example, Arabidopsis CRY2 undergoes blue light-dependent interaction with CIB1 (CRY2 Interacting bHLH1) to regulate flowering time (7-9). CRYs also suppress the E3 ubiquitin ligase activity of COP1 (CONSTITUTIVE PHOTOMORPHOGENIC 1) by forming a complex with SPA1 (SUPPRESSOR OF PHYA-105) and COP1 in a blue light-dependent manner (10-13). COP1 is a RING finger E3 ubiquitin ligase that acts downstream of phytochromes, cryptochromes, and UVR8 (UV Resistance Locus 8) (14,15) and is responsible for the degradation of various transcription factors in the dark, such as the bHLH transcription factor HFR1 (LONG HYPOCOTYL IN FAR RED1) and the bZIP factor HY5 (12,(16)(17)(18). Whether Arabidopsis CRY1 undergoes blue light-dependent interaction with transcription factors to regulate hypocotyl elongation is still unknown.In addition to light, ambient temperature serves as another key environmental cue that affects plant growth and development, but does not induce stress responses to any significant degree (19). Temperature regulates gene expression via chromatin remodeling and also regulation of transcription. It has been demonstrated that H2A.Z histone variant-containing nucleosomes act as thermosensors and mediate temperature induced transcriptome changes (20). PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) is a bHLH transcription factor directly link red light photoreceptor PHYTOCHROME B (PHYB) to light-regulated gene expression and plant development (21-23). PIF4 also plays a role in sensing high temperature, it not only regulates temperature-mediated floral induction in the short day condition through direct activation of FT (FLOWERING LOCUS T) (24), but it also controls high temperature-induced hypocotyl elongation by increasing free indo...
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