Project description:Mg batteries are a promising energy storage system because of the physicochemical merits of Mg as an anode material. However, the lack of electrochemically and chemically stable Mg electrolytes impedes the development of Mg batteries. In this study, a newly designed chloride-free Mg perfluorinated pinacolatoborate, Mg[B(O2 C2 (CF3 )4 )2 ]2 (abbreviated as Mg-FPB), was synthesized by a convenient method from commercially available reagents and fully characterized. The Mg-FPB electrolyte delivered outstanding electrochemical performance, specifically, 95 % Coulombic efficiency and 197 mV overpotential, enabling reversible Mg deposition, and an anodic stability of up to 4.0 V vs. Mg. The Mg-FPB electrolyte was applied to assemble a high voltage, rechargeable Mg/MnO2 battery with a discharge capacity of 150 mAh g-1 .
Project description:Achieving the full potential of magnesium-ion batteries (MIBs) is still a challenge due to the lack of adequate electrodes or electrolytes. Grignard-based electrolytes show excellent Mg plating/stripping, but their incompatibility with oxide cathodes restricts their use. Conventional electrolytes like bis(trifluoromethanesulfonyl)imide ((Mg(TFSI)2) solutions are incompatible with Mg metal, which hinders their application in high-energy Mg batteries. In this regard, alloys can be game changers. The insertion/extraction of Mg2+ in alloys is possible in conventional electrolytes, suggesting the absence of a passivation layer or the formation of a conductive surface layer. Yet, the role and influence of this layer on the alloys performance have been studied only scarcely. To evaluate the reactivity of alloys, we studied InSb as a model material. Ex situ X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy were used to investigate the surface behavior of InSb in both Grignard and conventional Mg(TFSI)2/DME electrolytes. For the Grignard electrolyte, we discovered an intrinsic instability of both solvent and salt against InSb. XPS showed the formation of a thick surface layer consisting of hydrocarbon species and degradation products from the solvent (THF) and salt (C2H5MgCl-(C2H5)2AlCl). On the contrary, this study highlighted the stability of InSb in Mg(TFSI)2 electrolyte.
Project description:ConspectusResearch at historically black colleges and universities (HBCUs) started with humble beginnings by G. W. Carver at Tuskegee Institute AL, the nation's first HBCU. He is now remembered as the man who transformed one crop, peanuts to more than 300 useful products such as food, beverages, medicines, cosmetics, and chemicals. However, research was not the focus of most of the newly founded HBCUs to provide, primarily, liberal arts education and training in agriculture for the black minority. HBCUs remained segregated, lacking facilities such as libraries and scientific/research equipment comparable to those at traditionally white institutions. While the Civil Rights Act of 1964 heralded the dawn of "equal opportunity" and progressive desegregation in the South, many public HBCUs had to close or merge with white institutions due to loss of funding and/or students. In order to remain competitive in enrollment and financial support of the best talents, HBCUs have been expanding their research and federal contracts by working in collaboration with research-intensive institutions and/or minority-serving institutions (MSIs). Albany State University (ASU), an HBCU with a great tradition of in-house and extramural undergraduate research, has partnered with the laboratory of Dr. John Miller at Brookhaven National Laboratory (BNL) to offer the best training and mentorship to our undergraduates. Students synthesized and performed conductivity measurements on a new generation of ion-pair salts. One of these constitutes, potentially, a nonaqueous electrolyte for the next generation of high-energy-density batteries owing to its electrochemical properties.The quest for rechargeable batteries with greater energy density and capable of shorter recharge time at the "pump" for electrical vehicles (EVs) is leading the development of electrolytes with higher ionic mobility and greater limiting conductivity. In order to achieve high energy density, it is vital for an electrolyte to be electrochemically stable while operating at high voltages.The development of a weakly coordinating anion/cation electrolyte for energy storage applications offers a challenge of technological significance. This class of electrolytes is advantageous for the investigation of electrode processes in low-polarity solvents. The improvement arises from the optimization of both ionic conductivity and solubility of the ion pair formed between a substituted tetra-arylphosphonium (TAPR) cation and tetrakis-fluoroarylborate (TFAB), a weakly coordinating anion. The chemical "push-pull" between cation and anion affords a highly conducting ion pair in low-polarity solvents such as tetrahydrofuran (THF) and tert-butyl methyl ether (TBME). The limiting conductivity value of the salt, namely, tetra-p-methoxy-phenylphosphonium-tetrakis(pentafluorophenyl)borate or TAPR/TFAB (R = p-OCH3), is in the range of lithium hexafluorophosphate (LiPF6) used in lithium-ion batteries (LIBs). This TAPR/TFAB salt can improve the efficiency and stability of batteries over those of existing and commonly used electrolytes by optimizing the conductivity tailored to the redox-active molecules. LiPF6 dissolved in carbonate solvents is unstable with high-voltage electrodes that are required to achieve greater energy density. In contrast, the TAPOMe/TFAB salt is stable and has a good solubility profile in low-polarity solvents given its relatively great size. And it constitutes a low-cost supporting electrolyte capable of bringing nonaqueous energy storage devices to compete with existing technologies.
Project description:The increasing use of low-cost lithium iron phosphate cathodes in low-end electric vehicles has sparked interest in Prussian blue analogues (PBAs) for lithium-ion batteries. A major challenge with iron hexacyanoferrate (FeHCFe), particularly in lithium-ion systems, is its slow kinetics in organic electrolytes and valence state inactivation in aqueous ones. We have addressed these issues by developing a polymeric cathode electrolyte interphase (CEI) layer through a ring-opening reaction of ethylene carbonate triggered by OH- radicals from structural water. This facile approach considerably mitigates the sluggish electrochemical kinetics typically observed in organic electrolytes. As a result, FeHCFe has achieved a specific capacity of 125 mAh g-1 with a stable lifetime over 500 cycles, thanks to the effective activation of Fe low-spin states and the structural integrity of the CEI layers. These advancements shed light on the potential of PBAs to be viable, durable, and efficient cathode materials for commercial use.
Project description:Protein engineering in the context of metabolic engineering is increasingly important to the field of industrial biotechnology. As the demand for biologically produced food, fuels, chemicals, food additives, and pharmaceuticals continues to grow, the ability to design and modify proteins to accomplish new functions will be required to meet the high productivity demands for the metabolism of engineered organisms. We review advances in selecting, modeling, and engineering proteins to improve or alter their activity. Some of the methods have only recently been developed for general use and are just beginning to find greater application in the metabolic engineering community. We also discuss methods of generating random and targeted diversity in proteins to generate mutant libraries for analysis. Recent uses of these techniques to alter cofactor use; produce non-natural amino acids, alcohols, and carboxylic acids; and alter organism phenotypes are presented and discussed as examples of the successful engineering of proteins for metabolic engineering purposes.
Project description:The Cas9 endonuclease of the CRISPR/Cas type IIA system from Streptococcus pyogenes is the heart of genome editing technology that can be used to treat human genetic and viral diseases. Despite its large size and other drawbacks, S. pyogenes Cas9 remains the most widely used genome editor. A vast amount of research is aimed at improving Cas9 as a promising genetic therapy. Strategies include directed evolution of the Cas9 protein, rational design, and domain swapping. The first generation of Cas9 editors comes directly from the wild-type protein. The next generation is obtained by combining mutations from the first-generation variants, adding new mutations to them, or refining mutations. This review summarizes and discusses recent advances and ways in the creation of next-generation genomic editors derived from S. pyogenes Cas9. KEY POINTS: • The next-generation Cas9-based editors are more active than in the first one. • PAM-relaxed variants of Cas9 are improved by increased specificity and activity. • Less mutagenic and immunogenic variants of Cas9 are created.
Project description:The solid-electrolyte interphase (SEI) is a key element in anode-electrolyte interactions and ultimately contributes to improving the lifespan and fast-charging capability of lithium-ion batteries. The conventional additive vinyl carbonate (VC) generates spatially dense and rigid poly VC species that may not ensure fast Li+ transport across the SEI on the anode. Here, a synthetic additive called isosorbide 2,5-dimethanesulfonate (ISDMS) with a polar oxygen-rich motif is reported that can competitively coordinate with Li+ ions and allow the entrance of PF6 - anions into the core solvation structure. The existence of ISDMS and PF6 - in the core solvation structure along with Li+ ions enables the movement of anions toward the anode during the first charge, leading to a significant contribution of ISDMS and LiPF6 to SEI formation. ISDMS leads to the creation of ionically conductive and electrochemically stable SEI that can elevate the fast-charging performance and increase the lifespan of LiNi0.8Co0.1Mn0.1O2 (NCM811)/graphite full cells. Additionally, a sulfur-rich cathode-electrolyte interface with a high stability under elevated-temperature and high-voltage conditions is constructed through the sacrificial oxidation of ISDMS, thus concomitantly improving the stability of the electrolyte and the NCM811 cathode in a full cell with a charge voltage cut-off of 4.4 V.
Project description:Cell-based therapeutics are an emerging modality with the potential to treat many currently intractable diseases through uniquely powerful modes of action. Despite notable recent clinical and commercial successes, cell-based therapies continue to face numerous challenges that limit their widespread translation and commercialization, including identification of the appropriate cell source, generation of a sufficiently viable, potent and safe product that meets patient- and disease-specific needs, and the development of scalable manufacturing processes. These hurdles are being addressed through the use of cutting-edge basic research driven by next-generation engineering approaches, including genome and epigenome editing, synthetic biology and the use of biomaterials.
Project description:Over the past few years, cellular immunotherapy has emerged as a novel treatment option for certain forms of hematologic malignancies with multiple CAR-T therapies now routinely administered in the clinic. The limitations of generating an autologous cell product and the challenges of toxicity with CAR-T cells underscore the need to develop novel cell therapy products that are universal, safe, and potent. Natural killer (NK) cells are part of the innate immune system with unique advantages, including the potential for off-the-shelf therapy. A recent first-in-human trial of CD19-CAR-NK infusion in patients with relapsed/refractory lymphoid malignancies proved safe with promising clinical activity. Building on these encouraging clinical responses, research is now actively exploring ways to further enhance CAR-NK cell potency by prolonging in vivo persistence and overcoming mechanisms of functional exhaustion. Besides these strategies to modulate CAR-NK cell intrinsic properties, there are increasing efforts to translate the successes seen in hematologic malignancies to the solid tumor space. This review will provide an overview on current trends and evolving concepts to genetically engineer the next generation of CAR-NK therapies. Emphasis will be placed on innovative multiplexed engineering approaches including CRISPR/Cas9 to overcome CAR-NK functional exhaustion and reprogram immune cell metabolism for enhanced potency.
Project description:A stable cathode-electrolyte interface (CEI) is crucial for aqueous zinc-ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode-electrolyte interface (CEI) in AZIBs. A water-soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion-dominated to capacitance-controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO- from SA acts as an anionic polyelectrolyte facilitating the adsorption of Zn2+ ; meanwhile fluoride atoms on PTFE backbone provide hydrophobicity to break desolvation penalty. The hybrid binder is beneficial in providing a higher areal flux of Zn2+ at the CEI, where the Zn-Birnessite MnO2 battery with the hybrid binder exhibits an average specific capacity 45.6% higher than that with conventional PVDF binders; moreover, a reduced interface activation energy attained fosters a superior rate capability and a capacity retention of 99.1% in 1000 cycles. The hybrid binder also reduces the cost compared to the PVDF/NMP, which is a universal strategy to modify interface morphology.