Solid-state Hybrid Research Articles

A Direct View on Li-Ion Transport and Li-Metal Plating in Inorganic and Hybrid Solid-State Electrolytes.

ConspectusDriven by the intrinsic safety and potential to achieve higher energy densities, solid-state Li-metal batteries are intensively researched. The ideal solid electrolyte should possess a high conductivity, should have electrochemical stability both toward the Li-metal anode and to high voltage cathodes, should suppress dendrites, should provide flexibility to deal with the volumetric changes of the electrodes, and should be easy to process. This challenging combination is to date not fulfilled by any solid electrolyte, be it organic, inorganic, or even a hybrid of the two. Pushing the development of solid electrolytes toward reversible room temperature operation when used in tandem with Li-metal anodes demands an understanding of critical processes that determine the properties of the solid electrolyte. These include the complex Li-ion transport as well as the Li-metal plating processes. This already presents the first experimental hurdle as the ability to directly and noninvasively monitor the Li-ion kinetics, Li densities, and Li chemistries, under in/situ or operando, is not trivial.The scope of this Account is the investigation and improvement of solid electrolytes, with the emphasis on the possibilities offered by solid-state NMR and neutron depth profiling as direct probes for the study of critical processes that involve Li ions and Li metal. Solid-state NMR allows us to unravel the complex interface chemical environment and the diffusion processes both in the bulk solid electrolyte and in the interface environment. These studies shed light on the role of interface composition, wetting and space-charge layers, on the macroscopic battery performance. Another technique that enables probing Li directly is operando neutron depth profiling, which allows us to determine the Li density as a function of depth. It provides a noninvasive and effectively nondestructive tool to examine delamination, irreversible reactions and dendrite formation during plating/stripping. Results demonstrate that it is very challenging to maintain the contact between Li metal and the SE during cycling, especially for the “anode-less” or “anode-free” configuration under low-pressure conditions. A perspective is provided on the potential improvement of the Li-ion transport, dendrite suppression, and preventing Li-metal-solid-electrolyte delamination as well as on the potential role of solid-state NMR and NDP techniques to guide these developments.

Mitigating Interfacial Mismatch between Lithium Metal and Garnet-Type Solid Electrolyte by Depositing Metal Nitride Lithiophilic Interlayer.

Solid-state lithium batteries are generally considered as the next-generation battery technology that benefits from inherent nonflammable solid electrolytes and safe harnessing of high-capacity lithium metal. Among various solid-electrolyte candidates, cubic garnet-type Li7La3Zr2O12 ceramics hold superiority due to their high ionic conductivity (10–3 to 10–4 S cm−1) and good chemical stability against lithium metal. However, practical deployment of solid-state batteries based on such garnet-type materials has been constrained by poor interfacing between lithium and garnet that displays high impedance and uneven current distribution. Herein, we propose a facile and effective strategy to significantly reduce this interfacial mismatch by modifying the surface of such garnet-type solid electrolyte with a thin layer of silicon nitride (Si3N4). This interfacial layer ensures an intimate contact with lithium due to its lithiophilic nature and formation of an intermediate lithium–metal alloy. The interfacial resistance experiences an exponential drop from 1197 to 84.5 Ω cm2. Lithium symmetrical cells with Si3N4-modified garnet exhibited low overpotential and long-term stable plating/stripping cycles at room temperature compared to bare garnet. Furthermore, a hybrid solid-state battery with Si3N4-modified garnet sandwiched between lithium metal anode and LiFePO4 cathode was demonstrated to operate with high cycling efficiency, excellent rate capability, and good electrochemical stability. This work represents a significant advancement toward use of garnet solid electrolytes in lithium metal batteries for the next-generation energy storage devices.

Flexible solid-state hybrid supercapacitors for the internet of everything (IoE)

The review provides the recent progress of flexible solid-state hybrid supercapacitors for portable and wearable energy storage devices in terms of design and performance with their state-of-the-art commercialized products for IoE applications.

Nonlinear optical response in coupled quantum wells optomechanical microcavity

We investigate the optical properties of a hybrid solid-state optomechanical microcavity containing two coupled quantum wells interacting with the cavity mode in the presence of a third-order nonlinear medium and a mechanically compliant distributed Bragg reflector (MC-DBR). The MC-DBR interacts with the cavity mode via the nonlinear radiation pressure effect. The steady state mean-field analysis shows the existence of optical bistability, which can be utilized to design all optical tunable switch. The coupling between the two quantum wells, the interaction between the excitons and the optical mode, the Kerr nonlinearity, and the optomechanical interaction can be tuned to operate the optical switch at lower input laser power. The fluctuation dynamics demonstrate the presence of optomechanically induced transparency (OMIT) and optomechanically induced absorption (OMIA). We find that both OMIT and OMIA can be manipulated efficiently by optomechanical coupling strength and the quantum well tunneling rate.

Coupling Bimetallic NiMn-MOF Nanosheets on NiCo2O4 Nanowire Arrays with Boosted Electrochemical Performance for Hybrid Supercapacitor

As promising electrode materials for supercapacitors, metal-organic frameworks (MOFs) with rich porosity, large surface area and abundant redox sites have attracted increasing attention. Nevertheless, the intrinsically interior electrical conductivity and ease of agglomeration for most MOFs have largely restricted their energy storage application. In this work, we report the controlled fabrication of bimetallic NiMn-MOF nanosheets on the surface of NiCo2O4 nanowire arrays to form NiCo2O4@NiMn-MOF core-shell structure and investigate the effect of Mn incorporation in Ni-MOF shell on the electrochemical performance of the hybrid arrays in supercapacitors. Benefitting from the delicately designed structures and compositions, the optimal NiCo2O4@NiMn-MOF electrode presents an extraordinarily high specific capacity of 243.0 mAh/g at 2 mA/cm2. We further assembled a flexible solid-state hybrid supercapacitor with NiCo2O4@NiMn-MOF and activated carbon as electrodes, exhibiting a high energy density of 48.2 Wh/kg at 1606.7 W/kg, accompanied by excellent mechanical flexibility and electrochemical durability. This work demonstrates a new approach for developing novel MOF array-based electrode materials with boosted electrochemical performance in the field of flexible energy storage devices.

Morphology–Ionic Conductivity Relationship in Polymer–Titania Hybrid Electrolytes for Lithium-Ion Batteries

The morphology and ionic conductivity of a high-molecular-weight polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer (DBC) solid-state hybrid electrolyte, prepared entirely from solution, containing the lithium salt LiTFSI ([Li]/[EO] = 0.1) and titania (TiO2) nanoparticles (NP) were investigated at different temperatures. Structure investigation using small-angle X-ray scattering (SAXS) indicates a rupture of the DBC morphology upon increasing TiO2–NP content, without a significant decrease in the ionic conductivity at high TiO2–NP contents. A high number of unbound charge carriers in the hybrid DBC electrolyte, achieved by careful tuning of the materials’ ratios, is the most important contribution to a high ionic conductivity.

Coupling a single NV center to a superconducting flux qubit via a nanomechanical resonator

We investigate the hybrid quantum system of a superconducting flux qubit, a single electronic spin associated with a negatively charged nitrogen vacancy (NV) center in diamond, and a high-quality magnetized nanomechanical resonator (NAMR). It is shown that the quantized motion of the NAMR can strongly couple to both the NV spin and the flux qubit. We estimate that the coupling strength of the NAMR to both the NV spin and the flux qubit can be about 2 π × 100 kHz, which is one order of magnitude larger than direct spin–qubit coupling. This enables the quantum state transfer to be faster and more robust against decoherence. The present work may provide an appealing way for quantum information processing based on hybrid solid-state quantum systems.

CNT assisted anomalous Li+ transport in CS/CMC solid biopolymer nanocomposite: an electrolyte in hybrid solid-state supercapacitors

CNT assisted anomalous Li+ transport in CS/CMC solid biopolymer nanocomposite: an electrolyte in hybrid solid-state supercapacitors

In Situ Binder-Free and Hydrothermal Growth of Nanostructured NiCo2S4/Ni Electrodes for Solid-State Hybrid Supercapacitors

Herein, we report a comparison of the electrochemical performance of two kinds of NiCo2S4-based electrodes for solid-state hybrid supercapacitors (HSCs). For the binder-free electrode, NiCo2S4 was grown on Ni foam by the chemical bath deposition (CBD) method. For the binder-using electrode, NiCo2S4 powder was synthesized by the hydrothermal method. FESEM images depicted the hierarchical nanostructure of NiCo2S4 synthesized by the hydrothermal method and uniform distribution of nanostructured NiCo2S4 grown on Ni foam by the CBD method. Half-cell studies of both NiCo2S4 electrodes showed them exhibiting battery-type charge storage behavior. To assemble HSCs, NiCo2S4 and activated carbon were used as a positive and negative electrode, respectively. Electrochemical studies of the HSCs showed that the accessible potential window was wide, up to 2.6 V, through cyclic voltammetry (CV) analysis. Chronopotentiometry (CP) studies revealed that the energy and power densities of binder-using HSC were 51.24 Wh/kg and 13 kW/kg at 1 Ag−1, respectively, which were relatively higher than those of the binder-free HSC. The binder-free HSC showed 52% cyclic stability, relatively higher than that of the binder-using HSC. Both HSCs, with unique benefits and burdens on energy storage performance, are discussed in this work.

The Embedded IoT Time Series Database for Hybrid Solid-State Storage System

IoT time series data is an important form of big data. How to improve the efficiency of storage system is crucial for IoT time series database to store and manage massive IoT time series data from various IoT devices. Mixing NVM and SSD is an effective method to improve the I/O performance of storage systems. However, there are great differences between HDD and NVM or SSD. As a result, NVM and SSD cannot be directly used in the current time series database effectively. We design an IoT time series database with an embedded engine in storage device drivers for the hybrid solid-state storage system consisting of NVM and SSD. The I/O software stack of storing and managing IoT time series data can be shortened to improve the efficiency. Based upon the intrinsic characteristics of IoT time series data and different features of NVM and SSD, a redundancy elimination and compression fusion strategy, a hierarchical management strategy, and a heterogeneous time series data index are designed to improve the efficiency. Finally, a prototype of embedded IoT time series database named TS-NSM is implemented, and YCSB-TS is used to measure the IOPS. The results show that TS-NSM can improve the write IOPS up to 243.6 times and 174.3 times, respectively, compared with InfluxDB and OpenTSDB, and improve the read IOPS up to 10.1 times and 14.4 times, respectively.

Emergent hydrodynamics in a strongly interacting dipolar spin ensemble.

Conventional wisdom holds that macroscopic classical phenomena naturally emerge from microscopic quantum laws1-7. However, despite this mantra, building direct connections between these two descriptions has remained an enduring scientific challenge. In particular, it is difficult to quantitatively predict the emergent 'classical' properties of a system (for example, diffusivity, viscosity and compressibility) from a generic microscopic quantum Hamiltonian7-14. Here we introduce a hybrid solid-state spin platform, where the underlying disordered, dipolar quantum Hamiltonian gives rise to the emergence of unconventional spin diffusion at nanometre length scales. In particular, the combination of positional disorder and on-site random fields leads to diffusive dynamics that are Fickian yet non-Gaussian15-20. Finally, by tuning the underlying parameters within the spin Hamiltonian via a combination of static and driven fields, we demonstrate direct control over the emergent spin diffusion coefficient. Our work enablesthe investigationof hydrodynamics in many-body quantum spin systems.

In Situ Synthesis of a Li6.4La3Zr1.4Ta0.6O12/Poly(vinylene carbonate) Hybrid Solid-State Electrolyte with Enhanced Ionic Conductivity and Stability

<i>In Situ</i> Synthesis of a Li_6.4La₃Zr_1.4Ta_0.6O₁₂/Poly(vinylene carbonate) Hybrid Solid-State Electrolyte with Enhanced Ionic Conductivity and Stability

Synthesis of 3D nanoflower-like mesoporous NiCo2O4 N-doped CNTs nanocomposite for solid-state hybrid supercapacitor; efficient material for the positive electrode

In this research work, we report a novel method for developing ternary NiCo2O4 compounds using deep eutectic solvents (DESs) and a strategy for improving their pseudocapacitive performance. NiCo2O4 composites with N-doped carbon nanotubes (NCNTs) were fabricated on Ni foam using a hydrothermal method. The electrochemical performance of the NiCo2O4 was altered with the change in the reaction temperature. The composite of NiCo2O4 and NCNTs demonstrated a maximum value of specific capacity of 303 mAh g−1 at a scan rate of 5 mV s−1. The specific capacity for the composite compound was 1.3-fold greater than that of the pristine NiCo2O4 sample. For practical applications, we constructed a flexible solid-state hybrid supercapacitor comprised of NiCo2O4/NCNTs//activated carbon (AC) cells with an excellent energy density of 12.31 Wh kg−1, outstanding power density of 8.96 kW kg−1, and tremendous electrode stability. The three-dimensional mesoporous nanoflowers and nanotubes-like nanostructures of NiCo2O4 are well-suited for use in hybrid devices as well as convenient for flexible electronic devices.

Construction of hierarchical Mn2O3 hollow microspheres derived from metal–organic frameworks for high performance supercapacitors

The application of Mn2O3 in supercapacitors usually faces the problems of poor conductivity and volume expansion during charging and discharging that lead to poor cycling stability. In this study, manganese-based metal−organic frameworks are designed as templates to construct hierarchical Mn2O3 hollow microspheres (Mn2O3-HMS) for supercapacitor electrodes. For a current density of 1 A g−1, Mn2O3-HMS delivers an ultrahigh specific capacitance of 1058 F g−1 comparable to the state-of-the-art results obtained for Mn2O3 composite materials. Moreover, the capacitance retention after 3500 cycles was approximately 90.2% at 10 A g−1. The superb performance of Mn2O3-HMS may be ascribed to the hierarchical structure and synergistic effect of the carbon matrix and oxygen vacancies. The unique structure of Mn2O3-HMS can shorten the electron and ion diffusion pathways and provide abundant redox active sites during cycling, while the carbon matrix and oxygen vacancy improve the charge transfer capability and accelerate the ion diffusion of Mn2O3-HMS. Furthermore, when Mn2O3-HMS is used as the cathode in flexible solid-state hybrid supercapacitors, the device displays an outstanding areal capacitance of 487.86 mF cm−2 at a current density of 1 mA cm−2.

Hybrid Solid State “Chaperone” Phases to Improve Solid State Sodium Electrolytes

Solid state electrolytes exhibiting high sodium-ion conductivity are promising elements in the advance of high energy density, low temperature molten sodium, solid state sodium, and sodium ion batteries. Traditional solid state Na+-ion conductors, such as β”-Al2O3 or NaSICON are reserved for high temperature operations (~300°C), not only to access higher Na+-ion conductivity, but also to facilitate wetting of molten sodium on the solid electrolyte. Lowering the operating temperature to near or below the ~98°C melting temperature of sodium for new sodium battery applications leads to poor interfacial wetting of the molten sodium to the ceramic electrolyte, increasing interfacial resistance in the cell and ultimately producing poor battery performance. Here, we explore the application of hybrid interfacial “chaperone” phases that dramatically improve physical and charge transfer interfaces between a NaSICON ceramic electrolyte and a metallic sodium anode. Through the application of material such as tin to the NaSICON surface, in-situ transformation during electrochemical cycling leads to the formation of hybrid metallic/intermetallic/ceramic interphases that facilitate efficient sodium wetting and charge transfer. We observe that these chaperone phases dramatically lower cell-limiting interfacial resistance, facilitating higher battery cycling current densities and better overall battery performance. Continued optimization of such functional interphase materials promises new advances in emerging sodium batteries. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Electrodeposition of Cu on PEDOT for a Hybrid Solid-State Electronic Device

Conductive polymers are nowadays attracting great attention for their peculiar mechanical, electrical and optical proprieties. In particular, PEDOT can be used in a wide range of innovative applications, from electroluminescent devices to photovoltaics. In this work, the electrochemical deposition of 3,4 ethylenedioxythiophene (EDOT) was performed on various substrates (ITO, thin films of gold and palladium on silicon wafers) by means of both potentiostatic and potentiodynamic techniques. This was intended to further expand the applications of electrochemically deposited PEDOT, particularly regarding the preparation of thin films in tight contact with electrode surfaces. This allows one to obtain systems prone to be used as electrodes in stacked devices. Chronoamperometric experiments were performed to study the nucleation and growth process of PEDOT. SEM, ESEM and AFM analysis allowed the characterization of the morphology of the polymeric films obtained. Raman and visible spectroscopy confirmed the high-quality of the coatings on the different substrates. Then, the PEDOT films were used as the base material for the further electrodeposition of a copper layer. In this way, a hybrid electronic device was obtained, by using electrochemical methods only. The high conductivity and ohmic behavior of the device were confirmed over a wide range of frequencies with electrical impedance spectroscopy analysis.

Ultra-low LPS/LLZO interfacial resistance – towards stable hybrid solid-state batteries with Li-metal anodes

To enable solid-state batteries with Li metal anodes, different classes of electrolytes are being investigated, mainly polymers, oxides, and sulfides. To overcome individual drawbacks of the material classes, so called bilayer hybrid cells combining layers of different electrolyte materials are considered highly promising. However, the introduction of an additional interface between the two solid electrolytes raises the question of the corresponding interfacial resistance. Herein, the properties of the interface between the two promising electrolytes Al-LLZO (Li6.16Al0.28La3Zr2O12) and LPS (Li7P3S11) are investigated by comprehensive impedance analyses. A series of systematic measurements allows to deconvolute the pressure dependence of the resistances related to the LPS material and the LPS/LLZO interface. This analysis reveals a significant pressure dependence of the LPS/LLZO interfacial resistance, mainly attributed to constriction resistance. Optimization of the LPS/LLZO interface is carried out by targeted surface treatment, resulting in a dramatic decrease of the interfacial resistance to virtually zero. These mechanistic studies and optimization approaches are complemented by practically relevant cycling tests using Li-metal electrodes. The cells show excellent cycling stability and negligible degradation. These findings contribute to the fundamental understanding of solid-solid interfaces in bilayer hybrid cells, indicating that solid-state batteries with hybrid LPS/LLZO electrolytes appear highly promising.

Deformation Behaviour of a FAST Diffusion Bond Processed from Dissimilar Titanium Alloy Powders

Titanium alloys have a high strength-to-weight ratio, fatigue performance and excellent corrosion resistance, and therefore are widely used in the aerospace sector due to their ability to withstand severe mechanical and thermal stresses in service. There are numerous cases where it would be desirable to use different titanium alloys in defined subcomponent regions to improve performance and efficiency. Conventional processing routes do not permit components to be produced with multiple titanium alloys and thus, design efficiency and optimization of component properties is compromised or over-engineered. In this study, a hybrid solid-state consolidation route is presented whereby field assisted sintering technology (FAST) is exploited to diffusion bond (DB) dissimilar titanium alloy powders in defined regions—a process termed FAST-DB. Titanium alloy powders Ti-6Al-4V (Ti-64) and Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) were bonded using FAST in order to study the tensile deformation behavior and strain localization across a dissimilar alloy solid-state bond. FAST-DB was carried out at the sub- and super- beta transus temperatures of both alloys to generate dissimilar microstructure morphologies across the bond. In all cases, diffusion bonds showed excellent structural integrity with no defects and a smooth hardness profile across the bond. The deformation characteristics of the bonds was studied using two different tensile test approaches. The first approach used ASTM standard specimens to measure the mechanical properties of FAST-DB samples and study the location of the tensile failure. The second approach used a microtester and optical Digital Image Correlation to capture the grain interaction in the bond region under tensile loading. The work demonstrated that the diffusion bond remains intact and that tensile failure occurs in Ti-64 (i.e. the lower strength alloy) and is independent of the grain crystal orientation. The results from this study will provide materials engineers confidence in nesting FAST-DB technology in future near net shape manufacturing routes.

Anomalous intra diffusive behavior of chitosan/PVDF solid polymer electrolytes and the enhancement of effective specific capacitance with nanostructured spinel MnCoFeO4 electrode in solid-state supercapacitors

Enhancement of conductivity in solid biopolymer electrolyte is an essential criterion for the fabrication of environment friendly solid-state supercapacitors. The conductivity of the blended polymer matrix composed of chitosan: PVDF (20: 80), salt LiClO4 (80 wt.%) and glycerol (15 wt.%) as plasticizer has increased by seven order in magnitude. The imaginary electric modulus (M″) is increased with increasing glycerol loading at higher frequency inferring a non-Debye type relaxation process. The anomalous intra diffusive behavior of the charge carriers inside the blended polymer matrix has been analyzed based on fractional diffusion model. Transport properties have also been studied from FTIR results. A hybrid solid-state supercapacitor has been developed with nano crystallites of manganese cobalt ferrite (MnCoFeO4) as electrode material and CS/PVDF blended polymer as solid state electrolyte. X-ray photoelectron spectroscopy (XPS) analysis of MnCoFeO4 reveals a partially inverse spinel structure with oxygen non-stoichiometry introduced by the mixed oxidation state of Mn ion. An unique model has been approached to evaluate inter ionic transport properties of the charge carriers in order to determine the effective specific capacitance of the electrode materials. A significant enhancement of effective specific capacitance of 750 Fg−1 has been achieved.

Solution-free self-assembled growth of ordered tricopper phosphide for efficient and stable hybrid supercapacitor

Herein, a solution-free dry strategy for the growth of self-assembled ordered tricopper phosphide (Cu3P) nanorod arrays is developed and the product is employed as a high-energy, stable positive electrode for a solid-state hybrid supercapacitor (HSC). The ordered Cu3P nanorod arrays grown on the copper foam deliver an excellent specific capacity of 664 mA h/g with an energy efficiency of 88% at 6 A/g and an ultra-long cycling stability over 15,000 continuous charge–discharge cycles. These electrochemical features are attributed to the ordered growth of the Cu3P nanorod arrays, which offers a large number of accessible electroactive sites, a reduced number of ion transfer paths, and reversible redox activity. The potential of the Cu3P nanorod arrays is further explored by engineering solid-state HSCs in which the nanorods are paired with an activated carbon-based negative electrode. The constructed cell is shown to convey a specific energy of 76.85 Wh/kg at a specific power of 1,125 W/kg and an 88% capacitance retention over 15,000 cycles. Moreover, the superior energy storing and delivery capacity of the cell is demonstrated by an energy efficiency of around 65%. The versatile solution-free dry strategies developed here pave the way towards engineering a range of electrode materials for next-generation energy storage systems.