Search

A Na–IrOx(OH)y cell using body fluid as the electrolyte demonstrates large charge storage capacity and long lifetime.

We report the synthesis of a Na-ion-conducting ionogel (IG) electrolyte using a one-pot, siloxane-modified sol–gel approach. The resulting pseudosolid electrolyte provides a nonflammable alternativ...

Two-dimensional (2D) semiconductors are attractive for electronic devices with atomically thin channels. However, controlling the electronic properties of the 2D materials by incorporating impurity dopants is inherently difficult due to the limited physical space in the atomically thin lattices. Here we show that a solid-state ionic doping approach can be used to tailor the carrier type in 2D semiconductors and create programmable devices. Our strategy exploits a superionic phase transition in silver iodide to induce switchable ionic doping. We create few-layer tungsten diselenide (WSe2) devices that can be reversibly transformed into transistors with reconfigurable carrier types and into diodes with switchable polarities by controllably poling the van der Waals integrated silver iodide above the superionic phase transition temperature. We also construct complementary logic gates by integrating and programming identical transistors, and show that the programmed functions can be erased by an external trigger (temperature or ultraviolet irradiation) to create the temporary and delible electronics that are desirable for electronic security. The superionic phase transition in silver iodide can be used to tailor the carrier type in two-dimensional tungsten diselenide and create programmable transistors, diodes and logic gates, the functions of which can be erased by external triggers such as ultraviolet irradiation.

It is well established that the miniaturization of batteries has not kept pace with the miniaturization of electronics. Three-dimensional (3D) batteries, which were developed with the intent of imp...

International audience; Electrochemical energy storage (EES) devices that provide high power and energy for micropower systems are considered to be essential for developing micro/nano electronics such as nanorobotics, environmental sensors, and connected smart electronics. One promising research direction in this field has been to develop on-chip EES devices whose length scales integrate with those of miniaturized electronic devices. In the work described here, we provide the first report of a hydroxide-ion-conducting solid electrolyte that can be patterned using standard lithography. By combining a negative photoresist with a polymerizable ionic liquid, we obtain a thermally and dimensionally stable, hydroxide-ion-conducting solid electrolyte with a conductivity of 10 mS cm−1. Patterning the solid electrolyte directly on interdigitated vanadium nitride (VN) electrodes enables a scalable fabrication approach for producing high-resolution, solid-state VN micro-supercapacitors (MSC) in both single and multiple devices.

Batteries and supercapacitors serve as the basis for electrochemical energy-storage devices. Although both rely on electrochemical processes, their charge-storage mechanisms are dissimilar, giving rise to different energy and power densities. Pseudocapacitive materials store charge through battery-like redox reactions but at fast rates comparable to those of electrochemical double-layer capacitors; these materials, therefore, offer a pathway for achieving both high energy and high power densities. Materials that combine these properties are in demand for the realization of fast-charging electrochemical energy-storage devices capable of delivering high power for long periods of time. In this Review, we describe the fundamental electrochemical properties of pseudocapacitive materials, with emphasis on kinetic processes and distinctions between battery and pseudocapacitive materials. In addition, we discuss the various types of pseudocapacitive materials, highlighting the differences between intrinsic and extrinsic materials; assess device applications; and consider the future prospects for the field. Pseudocapacitive materials can bridge the gap between high-energy-density battery materials and high-power-density electrochemical capacitor materials. In this Review, we examine the electrochemistry and physical signatures of pseudocapacitive charge-storage processes and discuss existing pseudocapacitive materials.

This study aims to investigate the thermal signature associated with the charge storage mechanisms in hybrid supercapacitors using in operando calorimetry under constant current cycling. The hybrid supercapacitors consisted of highly porous pseudocapacitive electrode and activated carbon (AC) electrode with either organic or aqueous electrolytes. Pseudocapacitive electrodes made of either molybdenum dioxide on reduced graphene oxide (MoO2-rGO) or manganese dioxide on graphene (MnO2-G) were synthesized to investigate heat generation associated with reversible redox reactions involving ion intercalation or fast surface redox reactions, respectively. Here, MoO2-rGO served as the negative electrode against activated carbon electrode in 1 M LiClO4 in EC:DMC. In addition, electrolyte consisting of 1 M TBABF4 in EC:DMC was also used as a reference to suppress redox reactions and intercalation due to its large ionic size. On the other hand, mesoporous MnO2-G electrode served as the positive electrode also against activated carbon electrode but in 0.5 M aqueous Na2SO4. First, a data analysis procedure was developed to distinguish between irreversible and reversible heat generation rates and to isolate Joule heating from the measured instantaneous heat generation rate at each electrode. In the AC electrodes, the irreversible heat generation rate was due to resistive losses (i.e., Joule heating) while the reversible heat generation was due to ion adsorption/desorption at the electrolyte/electrode interface. By contrast, irreversible heat generation rate in the pseudocapacitive electrodes exceeded Joule heating. This was attributed to irreversible heat generation associated with redox reactions, polarization heating, and hysteresis in EDL formation and dissolution. Finally, MoO2-rGO negative electrode in LiClO4 featured endothermic reversible heat generation during charging due to Li+ intercalation. Similarly, MnO2-G positive electrode in Na2SO4 featured endothermic heat generation during charging due to non-spontaneous surface redox reactions.

Ionogels, pseudo-solid-state electrolytes consisting of an ionic liquid electrolyte confined in a mesoporous inorganic matrix, have attracted interest recently due to their high ionic conductivity and physicochemical stability. These traits, coupled with their inherent solution processability, make them a viable solid electrolyte for solid-state battery systems. Despite the promising properties of ionogels, there have been very few investigations of the electrode–ionogel interface. In the present study, X-ray photoelectron spectroscopy, Raman spectroscopy, and electrochemical measurements were utilized to probe the surface reactions occurring at the electrode–ionogel interface for several electrode materials. Our results indicate that the sol acidity initiates breakdown of the organic constituents of the sol and reduction of the transition metals present in the electrode materials. This chemical attack forms an organic surface layer and affects the electrode composition, both of which can impede Li+ acces...

Conventional silicon-based fabrication techniques, ranging from photolithography to various etching processes, are well-established approaches for achieving high-resolution patterns for microelectronics in the semiconductor industry. Although the use of microfabrication methods in the production of electrochemical energy storage (EES) devices has not really been considered, the adaption of these silicon processing techniques can open up new fabrication routes especially for integrated on-chip energy storage devices. One important consideration for the development of on-chip EES devices is to fabricate a mechanically rigid solid electrolyte with spatial and thickness control, which can be achieved using photopatterning functionality.1 This presentation will review our results on the synthesis and characterization of a photopatternable, ionically conducting solid electrolyte for on-chip micro-supercapacitors (MSC). Our approach was to create ‘quasi-solid’ electrolytes in which the photopatternable epoxy-based polymer matrix (SU-8) confines charge-carrying ions to provide measurable ionic conductivity. The resulting ion modified electrolyte is a promising gel polymer electrolyte with excellent thermal and physical properties and a room temperature ionic conductivity of 10-4 S cm-1. In addition, we demonstrate wafer-scale fabrication of all-photopatterned solid-state MSC devices. Electrochemical testing of tandem MSC devices validated that the potential range and total current output of MSC devices can easily be tailored through modifying the device arrangements in series or parallel configurations. The proposed fabrication strategy, based on magnetron sputtering of electrode materials in conjunction with a photopatternable solid electrolyte, provides a unique opportunity for the development of robust solid-state MSC that can be integrated with microelectronics in a single chip. Reference 1. Choi, J. Lau, J. Hur, L. Smith, C. Wang, B. Dunn, Advanced Materials. 30 (2017) 1703772.

The miniaturization of electrochemical energy storage (EES) systems, one of the key challenges facing the rapid expansion of the Internet-of-Things, has been limited by poor performance of the various energy-storage components at the micrometer scale. Here, the development of a unique photopatternable porous separator that overcomes the electrolyte difficulties involving resistive losses at small dimensions is reported. The separator is based on modifying the chemistry of SU-8, an epoxy-derived photoresist, through the addition of a miscible ionic liquid. The ionic liquid serves as a templating agent, which is selectively removed by solution methods, leaving the SU-8 scaffold whose interconnected porosity provides ion transport from the confined liquid electrolyte. The photopatternable separator exhibits good electrochemical, chemical, thermal, and mechanical stability during the operation of electrochemical devices in both 2D and 3D formats. For the latter, the separator demonstrates the ability to form conformal coatings over 3D structures. The development of the photopatternable separator overcomes the electrolyte issues, which have limited progress in the field of micro-EES.

Herein we report the wafer-scale synthesis of thin-film black arsenic–phosphorus (b-AsP) alloys via two-step solid-source molecular beam deposition (MBD) and subsequent hermetic thermal annealing. We characterize our thin films with a variety of compositional and structural metrology techniques. X-ray photoelectron spectroscopy and energy dispersive spectroscopy determine compositions of As0.78P0.22 for our thin films, while X-ray reflectivity measurements indicate film thicknesses of 6–9 nm. High-resolution transmission electron spectroscopy images reveal a nanocrystalline morphology with orthorhombic b-AsP grains on the order of ∼5 nm. Raman scattering spectroscopy is employed to characterize the vibrational spectra of our thin films, and the results obtained are in agreement with previously reported b-AsP spectra. Evidence of uniform wafer-scale growth is substantiated by Raman mapping. We simulate crystal structure, band gaps, and Raman spectra from first-principles DFT-based computations and find exc...

The Lewis acid–base adduct approach has been widely used to form uniform perovskite films, which has provided a methodological base for the development of high-performance perovskite solar cells. However, its incompatibility with formamidinium (FA)-based perovskites has impeded further enhancement of photovoltaic performance and stability. Here, we report an efficient and reproducible method to fabricate highly uniform FAPbI3 films via the adduct approach. Replacement of the typical Lewis base dimethyl sulfoxide (DMSO) with N-methyl-2-pyrrolidone (NMP) enabled the formation of a stable intermediate adduct phase, which can be converted into a uniform and pinhole-free FAPbI3 film. Infrared and computational analyses revealed a stronger interaction between NMP with the FA cation than DMSO, which facilitates the formation of a stable FAI·PbI2·NMP adduct. On the basis of the molecular interactions with different Lewis bases, we proposed criteria for selecting the Lewis bases. Owed to the high film quality, per...

Summary Ionogels have recently attracted attention as pseudo-solid-state electrolytes based on their ability to confine an ionic liquid electrolyte within the mesoporous network of a sol-gel-derived inorganic matrix. Herein we report on the development of two important capabilities for ionogels. In one case, we incorporated spin-coated, 600-nm Li + -conducting ionogel films in electrochemical cells of LiFePO 4 /ionogel/Li. A key feature in this work is the ability to have the sol thoroughly penetrate the LiFePO 4 electrode prior to gelation. Devices operating at C/2 achieved capacities of 125 mAh/g for some 150 cycles with minimal capacity loss. In the second case, we developed a UV crosslinking synthesis method and demonstrated photo-patterning of the ionogel. The realization of a photo-patterned pseudo-solid-state electrolyte increases the versatility of ionogels and potentially enables new fabrication routes for electrochemical device architectures.

Metal phosphate compounds are considered promising candidates as positive electrode materials for Na-ion batteries because they offer higher cation-insertion potentials than analogous metal oxides. One such example is sodium iron fluorophosphate (Na2FePO4F), a compound that is typically synthesized by high-temperature solid-state routes. In this study, we prepare phase-pure Na2FePO4F using the polyol route, a low-temperature process that allows for the synthesis of nanoparticles (15–25 nm), a form that enhances Na-ion insertion kinetics and cycling stability. We then apply two methods to enhance the electronic conductivity of Na2FePO4F: (i) converting residual organic byproducts of the polyol synthesis to conductive carbon coatings; and (ii) preparing a nanocomposite with reduced graphene oxide. The resulting electrode materials are characterized in nonaqueous Na-ion electrolytes, assessing such metrics as specific capacity, rate capability, and cycling stability. A thorough electrochemical kinetics analysis is performed to deconvolve surface-vs.-bulk Na-ion insertion as a function of composite structure. Specific capacities between 60–110 mA h g−1 were achieved in galvanostatic charge–discharge tests when cycling in the range from 10C to C/10, respectively.

The operational instability of perovskite solar cells (PSCs) is known to mainly originate from the migration of ionic species (or charged defects) under a potential gradient. Compositional engineering of the A site cation of the ABX(3) perovskite structure has been shown to be an effective route to improve the stability of PSCs. Here, the effect of size-mismatch-induced lattice distortions on the ion migration energetics and operational stability of PSCs is investigated. It is observed that the size mismatch of the mixed A site composition films and devices leads to a steric effect to impede the migration pathways of ions to increase the activation energy of ion migration, which is demonstrated through multiple theoretical and experimental evidence. Consequently, the mixed composition devices exhibit significantly improved thermal stability under continuous heating at 85 degrees C and operational stability under continuous 1 sun illumination, with an extrapolated lifetime of 2011 h, compared to the 222 h of the reference device.

It is well established that the miniaturization of batteries has not kept pace with the miniaturization of electronics. Three-dimensional (3D) batteries, which were developed with the intent of improving microbattery performance, have had limited success because of fabrication challenges and material constraints. Solid-state, 3D batteries have been particularly susceptible to these shortcomings. In this paper we demonstrate that the incorporation of a high conductivity, solid electrolyte is the key to achieving a non-planar solid-state battery with high areal-capacity and high power-density. The model, 2.5D platform used in this study is a modification of the more typical 3D configuration in that it is comprised of a cathode array of pillars (3D) and a planar (2D) anode. This 2.5D geometry exploits the use of a high conductivity, ionogel electrolyte (10-3 S cm-1) which interpenetrates the 3D electrode array. The 2.5D battery offers high areal energy densities from the post array while the high-conductivity, solid electrolyte enables high power densities (3.7 mWh cm-2 at 2.8 mW cm-2). The reported solid-state 2.5D device exceeds the energy and power densities of any 3D solid-state system and the derived multiphysics model provides guidance for achieving significantly higher energy and power densities.

The limitations of current microbattery designs is best highlighted by the restricted electrochemical performance of planar cells stemming from their long diffusion path lengths, or by the fabrication and material constraints of recent, novel 3D-electrode architectures. Herein, the fabrication and properties of a multidimensional, high areal-capacity, 2.5D battery are described as means to address the limitations of planar and 3D-electrode designs. Our 2.5D battery, composed of a 3D LiFePO4 array and a planar Li anode, provides a way to achieve high energy densities, while utilization of a high ionic conductivity, solution-processed ionogel electrolyte enables high power densities (4.1 mWh cm-2 at 2.8 mW cm-2). This 2.5D design exhibits improved or comparable energy and power densities to the best 3D batteries in literature, while simplifying the fabrication process, eliminating the liquid electrolyte, and facilitating an easily customizable battery. The exemplary performance and simple fabrication process of the 2.5D design, possible because of the ionogel electrolyte, presents a promising direction for the integration of energy-storage devices into on-chip and microelectronic applications that is impractical with current high-performance 3D-battery designs. Figure 1

Two HIV-1-infected children on antiretroviral therapy were enrolled into a clinical study of retroviral-mediated transfer of a gene that inhibits replication of HIV-1, targeting bone marrow CD34+ hematopoietic stem/progenitor cells. Two retroviral vectors were used, one encoding a "humanized" dominant-negative REV protein (huM10) that is a potent inhibitor of HIV-1 replication and one encoding a nontranslated marker gene (FX) to serve as an internal control for the level of gene marking. Peripheral blood mononuclear cells (PBMC) containing the huM10 gene or FX gene were detected by quantitative PCR at frequencies of approximately 1/10,000 in both subjects for the first 1-3 months following re-infusion of the gene-transduced bone marrow, but then were at or below the limits of detection (

One of the important considerations for the development of on-chip batteries is the need to photopattern the solid electrolyte directly on electrodes. Herein, the photopatterning of a lithium-ion conducting solid electrolyte is demonstrated by modifying a well-known negative photoresist, SU-8, with LiClO4. The resulting material exhibits a room temperature ionic conductivity of 52 µS cm−1 with a wide electrochemical window (>5 V). Half-cell galvanostatic testing of 3 µm thin films spin-coated on amorphous silicon validates its use for on-chip energy-storage applications. The modified SU-8 possesses excellent mechanical integrity, is thermally stable up to 250 °C, and can be photopatterned with micrometer-scale resolution. These results present a promising direction for the integration of electrochemical energy storage in microelectronics.

Objective Nonmyeloablative cytoreduction is used in clinical hematopoietic stem cell gene therapy trials to increase engraftment of gene-modified cells. We utilized an infant rhesus monkey model to identify an optimal dosage of busulfan that results in efficient long-term gene marking with minimal toxicities. Methods Bone marrow (BM) was harvested, followed by a single 2-hour intravenous infusion of busulfan at escalating dosages of 0 to 160 mg/m 2 . CD34 + cells were immunoselected from BM, transduced overnight with a simian immunodeficiency virus–based lentiviral vector carrying a nonexpressed marker gene, and injected intravenously 48 hours post–busulfan administration. Pharmacokinetics were assessed, as well as adverse effects and peripheral blood and BM gene marking. Results Increasing dosages of busulfan resulted in increased area-under-the-curve (AUC) with some variability at each dosage level, suggesting interindividual variation in clearance. Blood chemistries were normal and no adverse effects were observed as a result of busulfan infusion. At 120 and 160 mg/m 2 , transient neutropenia and thrombocytopenia were noted but not lymphopenia. Over the 6 months of study posttransplantation, a busulfan dosage-related increase in gene marking was observed ranging from undetectable (no busulfan) up to 0.1% gene-containing cells in animals achieving the highest busulfan AUC. This corresponds to a more than 100-fold increase in gene marking over the busulfan dosage range studied. Conclusions These data indicate that increased gene marking of hematopoietic stem cells can be achieved by escalating busulfan dosages from 40 to 160 mg/m 2 without significant toxicity in infant nonhuman primates.

Top of pageAbstract In clinical allogeneic bone marrow transplantation (BMT), complete myeloablation with high-dose busulfan (16 mg/kg) is often used to |[ldquo]|make space|[rdquo]| for the graft in the recipient BM compartment. As this treatment has significant toxicity, we sought to establish a low-dose busulfan protocol for partial myeloablation in the context of a gene-modified autologous BMT. Also, for infants and young children, calculation of dosage based on body surface area (mg/m2) has been reported give more consistent circulating busulfan levels than dosages based on mass (kg). In this study we sought to identify an optimal busulfan dose that could result in efficient long-term gene marking with minimal toxicities. We performed a lentiviral gene-marking study in infant rhesus macaques using escalating doses of busulfan. BM (|[sim]|10 ml/kg) was collected for immunoselection, and followed by a single 2 hour i.v. infusion of busulfan. Monkeys were transplanted using busulfan at 0, 40, 80, 120, and 160 mg/m2. Peripheral blood (PB) samples were collected for pharmacokinetic analysis up to 4 hours post-infusion, and the area under the curve (AUC) was determined. Isolated CD34+ cells were cultured for 24 hours in X-Vivo 15 with 100 ng/ml each of SCF, Flt3-L, and TPO. CD34+ cells were then transduced overnight with 4|[times]|10e7 infectious particles/ml of Simian Immunodeficiency Virus (SIV)-derived lentiviral vector pseudotyped with VSV-G on fibronectin-coated plates and using 4 |[mu]|g/ml protamine sulfate. The SIV vector contains a neomycin gene with a mutation in the start codon that abolishes its expression, and can therefore serve as a non-expressed marker gene. Transduced cells were washed and reinfused i.v 48 hours after administration of busulfan. Animals were monitored for myelosuppression, toxicity, and immune function. Increasing dosages of busulfan resulted in increased AUC. Some variability in AUC at each dose level was observed, suggesting inter-individual variations in busulfan absorption and clearance. At busulfan doses of 120 and 160 mg/m2, neutrophil and platelet counts transiently declined and were dose-dependent. No lymphopenia was observed, consistent with busulfan being myeloablative, but not immunosuppressive. Blood chemistries and behavior were normal in all animals, and no abnormalities were observed. PB and BM samples collected monthly were analyzed by real-time PCR to quantify gene marking. Gene marking levels have been fairly constant over the first 4 months post-transplant, ranging from undetectable in animals receiving no busulfan up to 0.1 % gene-containing cells in animals with the highest busulfan AUC. Together, these preliminary data suggest that (1) increased gene marking can be achieved by escalating busulfan doses, (2) busulfan is safe at the sub-myeloablative doses studied, and (3) while the anticipated myelosuppressive effects of busulfan were observed, there has been no evidence of adverse findings, to date.