Towards maximized volumetric capacity via pore-coordinated design for large-volume-change lithium-ion battery anodes

To achieve the urgent requirement for high volumetric energy density in lithium-ion batteries, alloy-based anodes have been spotlighted as next-generation alternatives. Nonetheless, for the veritable accomplishment with regards to high-energy demand, alloy-based anodes must be evaluated considering several crucial factors that determine volumetric capacity. In particular, the electrode swelling upon cycling must be contemplated if these anodes are to replace conventional graphite anodes in terms of volumetric capacity. Herein, we propose macropore-coordinated graphite-silicon composite by incorporating simulation and mathematical calculation of numerical values from experimental data. This unique structure exhibits minimized electrode swelling comparable to conventional graphite under industrial electrode fabrication conditions. Consequently, this hybrid anode, even with high specific capacity (527 mAh g(-1)) and initial coulombic efficiency (93%) in half-cell, achieves higher volumetric capacity (493.9 mAh cm(-3)) and energy density (1825.7 Wh L-1) than conventional graphite (361.4 mAh cm(-3) and 1376.3 Wh L-1) after 100 cycles in the full-cell configuration

Direct binding of TFEα opens DNA binding cleft of RNA polymerase

Opening of the DNA binding cleft of cellular RNA polymerase (RNAP) is necessary for transcription initiation but the underlying molecular mechanism is not known. Here, we report on the cryo-electron microscopy structures of the RNAP, RNAP-TFEα binary, and RNAP-TFEα-promoter DNA ternary complexes from archaea, Thermococcus kodakarensis (Tko). The structures reveal that TFEα bridges the RNAP clamp and stalk domains to open the DNA binding cleft. Positioning of promoter DNA into the cleft closes it while maintaining the TFEα interactions with the RNAP mobile modules. The structures and photo-crosslinking results also suggest that the conserved aromatic residue in the extended winged-helix domain of TFEα interacts with promoter DNA to stabilize the transcription bubble. This study provides a structural basis for the functions of TFEα and elucidates the mechanism by which the DNA binding cleft is opened during transcription initiation in the stalk-containing RNAPs, including archaeal and eukaryotic RNAPs

Replacing conventional battery electrolyte additives with dioxolone derivatives for high-energy-density lithium-ion batteries

Solid electrolyte interphases generated using electrolyte additives are key for anode-electrolyte interactions and for enhancing the lithium-ion battery lifespan. Classical solid electrolyte interphase additives, such as vinylene carbonate and fluoroethylene carbonate, have limited potential for simultaneously achieving a long lifespan and fast chargeability in high-energy-density lithium-ion batteries (LIBs). Here we report a next-generation synthetic additive approach that allows to form a highly stable electrode-electrolyte interface architecture from fluorinated and silylated electrolyte additives; it endures the lithiation-induced volume expansion of Si-embedded anodes and provides ion channels for facile Li-ion transport while protecting the Ni-rich LiNi0.8Co0.1Mn0.1O2 cathodes. The retrosynthetically designed solid electrolyte interphase-forming additives, 5-methyl-4-((trifluoromethoxy)methyl)-1,3-dioxol-2-one and 5-methyl-4-((trimethylsilyloxy)methyl)-1,3-dioxol-2-one, provide spatial flexibility to the vinylene carbonate-derived solid electrolyte interphase via polymeric propagation with the vinyl group of vinylene carbonate. The interface architecture from the synthesized vinylene carbonate-type additive enables high-energy-density LIBs with 81.5% capacity retention after 400 cycles at 1???C and fast charging capability (1.9% capacity fading after 100 cycles at 3???C)

Cryo-EM structure of human Cx31.3/GJC3 connexin hemichannel

Connexin family proteins assemble into hexameric channels called hemichannels/connexons, which function as transmembrane channels or dock together to form gap junction intercellular channels (GJIChs). We determined the cryo-electron microscopy structures of human connexin 31.3 (Cx31.3)/GJC3 hemichannels in the presence and absence of calcium ions and with a hearing-loss mutation R15G at 2.3-, 2.5-, and 2.6-A resolutions, respectively. Compared with available structures of GJICh in open conformation, Cx31.3 hemichannel shows substantial structural changes of highly conserved regions in the connexin family, including opening of calcium ion-binding tunnels, reorganization of salt-bridge networks, exposure of lipid-binding sites, and collocation of amino-terminal helices at the cytoplasmic entrance. We also found that the hemichannel has a pore with a diameter of ~8 A and selectively transports chloride ions. Our study provides structural insights into the permeant selectivity of Cx31.3 hemichannel

?????? ?????? ????????? ?????? ?????? ?????? ?????? ?????????

Department of Energy Engineering (Battery Science and Technology)The emerging market of portable devices and electric vehicles necessitates research on lithium-ion batteries (LIBs) with high energy density and long cycle life. Although conventional graphite anode has been widely used for LIBs, it still has limitation to realize high energy density LIBs because of the low theoretical capacity of 372 mAh g-1. To address the issue, alloy anodes (Si and SiO) with their high theoretical capacity (3579 and ~1500 mAh g-1) have been intensively studied as promising alternatives for next generation anode. However, their large volume change during cycling giving rise to the crack formation, accompanying unstable solid-electrolyte interphase (SEI) layer, accelerates degradation of alloy anodes. As a result, fundamental studies need to be pursued to develop alloy anodes materials with high energy density and long cycle life. In my dissertation, developed analysis and electrochemical estimation will be conducted to investigate capacity fading mechanism of alloy anodes, stemming from behavior of SEI layer, crack formation and aggregation during cycling. Then, several types of strategies, such as nanomaterial design, will be applied to minimizing the degradation of alloy anodes. These strategies could be hopefully the solution to enhance the electrochemical performance and breakthrough technology to replace the conventional graphite for portable devices or electric vehicles application.clos

Issues impeding the commercialization of laboratory innovations for energy-dense Si-containing lithium-ion batteries

Silicon is a promising alternative to the conventional graphite anode in high-energy lithium-ion batteries owing to its high gravimetric capacity. However, intrinsic issues, such as severe volume expansion during cycling, have plagued the development of batteries that use Si anodes. While tremendous progress has been made in laboratories to tackle these issues, most Si-containing batteries in industry, in which Si anodes are made of Si suboxides or Si-C composites, can use only a very limited amount of Si. Here we review important factors that affect the practical energy density of Si-containing batteries, including electrode swelling and cut-off voltage in cell operation. We also discuss calendar life, safety and cost issues, which also have a strong influence on practical cell design. Furthermore, we propose testing protocols to evaluate the practical viability of newly developed Si anodes.,Substantial gaps exist between laboratory innovations and practical applications of Si-based batteries. Here the authors survey critical factors that hinder the development of practical Si-based anodes and propose testing protocols to evaluate laboratory innovations.

Dendrite-free lithium deposition on conventional graphite anode by growth of defective carbon-nanotube for lithium-metal/ion hybrid batteries

Conventional graphite faces theoretical capacity limitation, and conventional cells using graphite should have a sufficient N/P ratio to avoid lithium plating on the surface of graphite. This lithium plating not only causes severe cell degradation due to its poor reversibility but also causes critical safety issues by penetrating the separator. In this study, we present defective carbon-nanotube-grown graphite that has a high affinity for lithium deposition for electrochemical lithiation. These lithiophilic defective carbon nanotubes can result in densely packed lithium deposition without any dendritic lithium plating, causing poor reversibility and fatal safety issues. We observed that the dense lithium deposition on the defective-carbon-nanotube grown graphite provides three times denser deposition and 13% improved initial coulombic efficiency than dendritic lithium deposition on pristine graphite. As a result, in a full-cell evaluation, the lithiophilic defective carbon growth graphite showed excellent cycle stability (83.7%) over 300 cycles even with a reverse designed N/P ratio (0.8), which can increase the energy density by reducing the amount of anode and introducing lithium metal deposition on the anode surface

Snail and Cox-2 expressions are associated with WHO tumor grade and survival rate of patients with gliomas

The transcriptional factor Snail and enzyme cyclo-oxygenase-2 (Cox-2) are suggested to be important effectors of invasiveness and tumorigenesis in various tumors. Tumors of higher grade have the propensity for tumor cell migration and invasiveness. This study was performed in order to evaluate the association between Snail and Cox-2 expressions and their values as prognostic factors in various grades of glioma, Specimens of 56 patients with glioma were used in the study. Univariate analysis showed that WHO tumor grade, and expressions of Snail and Cox-2 were significant prognostic factors affecting overall and disease progression-free survival rates. In the multivariate analysis by Cox regression model, only WHO tumor grade was shown to be a significant independent prognostic factor of overall and progression-free survival rates. In conclusion, Snail and Cox-2 expressions were associated with WHO grade in gliomas and may be used as prognostic indicators.Onguru O, 2008, NEUROPATHOLOGY, V28, P29, DOI 10.1111/j.1440-1789.2007.00828.xD`Abaco GM, 2007, J CLIN NEUROSCI, V14, P1041, DOI 10.1016/j.jocn.2007.06.019Yin T, 2007, J SURG RES, V141, P196, DOI 10.1016/j.jss.2006.09.027Martinez R, 2007, J NEURO-ONCOL, V83, P91, DOI 10.1007/s11060-006-9292-0Wong MLH, 2007, J CLIN NEUROSCI, V14, P301, DOI 10.1016/j.jocn.2006.11.005Weingart J, 2007, J CLIN ONCOL, V25, P399, DOI 10.1200/JCO.2006.06.6290Ding JX, 2006, GYNECOL ONCOL, V103, P623, DOI 10.1016/j.ygyno.2006.04.023Onguru O, 2006, CLIN NEUROPATHOL, V25, P216Dohadwala M, 2006, CANCER RES, V66, P5338, DOI 10.1158/0008-5472.CAN-05-3635Kyo S, 2006, HUM PATHOL, V37, P431, DOI 10.1016/j.humpath.2005.12.021Phillips HS, 2006, CANCER CELL, V9, P157, DOI 10.1016/j.ccr.2006.02.019Layfield LJ, 2006, APPL IMMUNOHISTO M M, V14, P91Wick W, 2006, CURR PHARM DESIGN, V12, P341Entz-Werle N, 2005, INT J CANCER, V117, P349, DOI 10.1002/ijc.21068Koul D, 2005, MOL CANCER THER, V4, P1681, DOI 10.1158/1535-7163.MCT-05-0258Quinn JA, 2005, J CLIN ONCOL, V23, P7178, DOI 10.1200/JCO.2005.06.502Elias MC, 2005, NEOPLASIA, V7, P824, DOI 10.1593/neo.04352Lippman SM, 2005, CLIN CANCER RES, V11, P6097, DOI 10.1158/1078-0432.CCR-05-1217Jorda M, 2005, J CELL SCI, V118, P3371, DOI 10.1242/jcs.02465Kwok WK, 2005, CANCER RES, V65, P5153Martin TA, 2005, ANN SURG ONCOL, V12, P488, DOI 10.1245/ASO.2005.04.010Kaur B, 2005, NEURO-ONCOLOGY, V7, P134, DOI 10.1215/S1152851704001115KESARI S, 2005, CURR NEUROL NEUROSCI, V5, P186Morokoff AP, 2004, J CLIN NEUROSCI, V11, P807, DOI 10.1016/j.jocn.2004.03.004Kajita M, 2004, MOL CELL BIOL, V24, P7559, DOI 10.1128/MCB.24.17.7559-7566.2004Hara A, 2004, ACTA NEUROPATHOL, V108, P43, DOI 10.1007/s00401-004-0860-0Yang J, 2004, CELL, V117, P927Vega S, 2004, GENE DEV, V18, P1131, DOI 10.1101/gad.294104Onguru O, 2004, ENDOCR PATHOL, V15, P17Peinado HC, 2004, INT J DEV BIOL, V48, P365Dannenberg AJ, 2003, CANCER CELL, V4, P431Seki K, 2003, J BIOL CHEM, V278, P41862, DOI 10.1074/jbc.M308336200Lin CD, 2003, AM J CLIN ONCOL-CANC, V26, pS98Sugimachi K, 2003, CLIN CANCER RES, V9, P2657Guaita S, 2002, J BIOL CHEM, V277, P39209, DOI 10.1074/jbc.M206400200Fraga ME, 2002, BIOTECHNIQUES, V33, P632Zhu YA, 2002, NAT REV CANCER, V2, P616, DOI 10.1038/nrc866Hajra KM, 2002, GENE CHROMOSOME CANC, V34, P255, DOI 10.1002/gcc.10083Thiery JP, 2002, NAT REV CANCER, V2, P442, DOI 10.1038/nrc822Blanco MJ, 2002, ONCOGENE, V21, P3241Nieto MA, 2002, NAT REV MOL CELL BIO, V3, P155, DOI 10.1038/nrm757FRAGA MF, 2002, BIOTECHNIQUES, V33, P636FRAGA MF, 2002, BIOTECHNIQUES, V33, P634Comijn J, 2001, MOL CELL, V7, P1267Shono T, 2001, CANCER RES, V61, P4375Arias AM, 2001, CELL, V105, P425Esteller M, 2000, NEW ENGL J MED, V343, P1350Hemavathy K, 2000, GENE, V257, P1Joki T, 2000, CANCER RES, V60, P4926Grooteclaes ML, 2000, ONCOGENE, V19, P3823Cano A, 2000, NAT CELL BIOL, V2, P76Batlle E, 2000, NAT CELL BIOL, V2, P84Dannenberg AJ, 1999, SEMIN ONCOL, V26, P499Christofori G, 1999, TRENDS BIOCHEM SCI, V24, P73Jaeckle KA, 1998, J CLIN ONCOL, V16, P3310Knott JCA, 1998, INT J CANCER, V75, P864Huang M, 1998, CANCER RES, V58, P1208Silber JR, 1998, CANCER RES, V58, P1068AGOSTI RM, 1992, VIRCHOWS ARCH A, V420, P321BEHRENS J, 1992, SEMIN CELL BIOL, V3, P169BIGNER SH, 1990, CANCER RES, V50, P8017

Origin of extremely large magnetoresistance in the candidate type-II Weyl semimetal MoTe2-x

The recent observation of extremely large magnetoresistance (MR) in the transition-metal dichalcogenide MoTe2 has attracted considerable interest due to its potential technological applications as well as its relationship with novel electronic states predicted for a candidate type-II Weyl semimetal. In order to understand the origin of the MR, the electronic structure of MoTe2-x (x = 0.08) is systematically tuned by application of pressure and probed via its Hall and longitudinal conductivities. With increasing pressure, a monoclinic-to-orthorhombic (1T' to T-d) structural phase transition temperature (T*) gradually decreases from 210 K at 1 bar to 58 K at 1.1 GPa, and there is no anomaly associated with the phase transition at 1.4 GPa, indicating that a T = 0 K quantum phase transition occurs at a critical pressure (P-c) between 1.1 and 1.4 GPa. The large MR observed at 1 bar is suppressed with increasing pressure and is almost saturated at 100% for P > P-c. The dependence on magnetic field of the Hall and longitudinal conductivities of MoTe2-x shows that a pair of electron and hole bands are important in the low-pressure T-d phase, while another pair of electron and hole bands are additionally required in the high-pressure 1T' phase. The MR peaks at a characteristic hole-to-electron concentration ratio (n(c)) and is sharply suppressed when the ratio deviates from n(c) within the T-d phase. These results establish the comprehensive temperature-pressure phase diagram of MoTe2-x and underscore that its MR originates from balanced electron-hole carrier concentrations. © The Author(s) 201