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Reticular chemistry provides opportunities to design solid-state electrolytes (SSEs) with modular tunability. However, SSEs based on modularly designed crystalline metal–organic frameworks (MOFs) often require liquid electrolytes for interfacial contact. Monolithic glassy MOFs can have liquid processability and uniform lithium conduction, which is promising for the reticular design of SSE without liquid electrolytes. Here, we develop a generalizable strategy for the modular design of noncrystalline SSEs based on a bottom-up synthesis of glassy MOFs. We demonstrate such a strategy by linking polyethylene glycol (PEG) struts and nanosized titanium-oxo clusters into network structures termed titanium alkoxide networks (TANs). The modular design allows the incorporation of PEG linkers with different molecular weights, which give optimal chain flexibility for high ionic conductivity, and the reticular coordinative network provides a controlled degree of cross-linking that gives adequate mechanical strength. This research shows the power of reticular design in noncrystalline molecular framework materials for SSEs.

Lithium extraction from seawater/brine has attracted increasing attention because of its abundant reserves. However, most extraction technologies require extra energy consumption to enrich lithium in the solution. Here, we develop a self-driven lithium extraction method by a composite asymmetric nonwoven (CAN) with directional liquid transport functionality. CAN consists of one hydrophobic fibrous layer containing Li-ion sieve particles and one hydrophilic fibrous layer. As a result, a solution containing various types of ions can spontaneously transport through CAN from the hydrophobic to the hydrophilic layer, absorbing Li ions in the hydrophobic layer. CAN exhibits high Li+selective adsorption capacity, good chemical stability, easy recyclability, and long service life. Importantly, extremely low energy of ∼1.631 J is consumed on extracting 1 mg lithium ion by our method using CAN. This work opens a great promise of saving huge energy costs on lithium extraction from seawater or salt lakes.

Thin films with effective ion sieving ability are highly desired in energy storage and conversion devices, including batteries and fuel cells. However, it remains challenging to design and fabricate cost-effective and easy-to-process ultrathin films for this purpose. Here, we report a 300 nm-thick functional layer based on porous organic cages (POCs), a new class of porous molecular materials, for fast and selective ion transport. This solution processable material allows for the design of thin films with controllable thickness and tunable porosity by tailoring cage chemistry for selective ion separation. In the prototype, the functional layer assembled by CC3 can selectively sieve Li+ions and efficiently suppress undesired polysulfides with minimal sacrifice for the system’s total energy density. Separators modified with POC thin films enable batteries with good cycle performance and rate capability and offer an attractive path toward the development of future high-energy-density energy storage devices.

In this work, a GaN-based UV photodetector with an asymmetric electrode structure was fabricated by atomic layer deposition (ALD) of TiN layers. The thickness of the TiN can be monitored in situ by a quartz crystal microbalance (QCM) and precisely controlled through the modulation of deposition cycles. During the ALD process, periodic variation in the QCM frequency was observed and correlated to the physical adsorption, chemical bonding, and the excessive precursor exhaust, which included tetrakis(dimethylamino)titanium (TDMAT) and N sources. The asymmetric TiN/GaN/TiN photodetector showed excellent photosensing performance, with a UV-visible rejection ratio of 173, a responsivity of 4.25 A/W, a detectivity of 1.1×10^13 Jones, and fast response speeds (a rise time of 69 μs and a decay time of 560 μs). Moreover, the device exhibits high stability, with an attenuation of only approximately 0.5% after 360?nm light irradiation for 157 min. This result indicates the potential of TiN as a transparent contact electrode for GaN-based optoelectronic devices.

Balancing interfacial stability and Li+transfer kinetics through surface engineering is a key challenge in developing high-performance battery materials. Although conformal coating enabled by atomic layer deposition (ALD) has shown great promise in controlling impedance increase upon cycling by minimizing side reactions at the electrode–electrolyte interface, the coating layer itself usually exhibits poor Li+conductivity and impedes surface charge transfer. In this work, we have shown that by carefully controlling postannealing temperature of an ultrathin ZrO2film prepared by ALD, Zr4+surface doping could be achieved for Ni-rich layered oxides to accelerate the charge transfer yet provide sufficient protection. Using single-crystal LiNi0.6Mn0.2Co0.2O2as a model material, we have shown that surface Zr4+doping combined with ZrO2coating can enhance both the cycle performance and rate capability during high-voltage operation. Surface doping via controllable postannealing of ALD surface coating layer reveals an attractive path toward developing stable and Li+-conductive interfaces for single-crystal battery materials.

High-voltage lithium cobalt oxide (LiCoO2) has the highest volumetric energy density among commercial cathode materials in lithium-ion batteries due to its high working voltage and compacted density. However, under high voltage (4.6 V), the capacity of LiCoO2fades rapidly due to parasitic reactions of high-valent cobalt with the electrolyte and the loss of lattice oxygen at the interface. In this study, we report a temperature-driven anisotropic doping phenomenon of Mg2+that results in surface-populated Mg2+doping to the side of the (003) plane of LiCoO2. Mg2+dopants enter the Li+sites, lower the valence state of Co ions with less hybridization between the O 2p and Co 3d orbitals, promote the formation of surface Li+/Co2+anti-sites, and suppress lattice oxygen loss on the surface. As a result, the modified LiCoO2demonstrates excellent cycling performance under 4.6 V, reaching an energy density of 911.2 Wh/kg at 0.1C and retaining 92.7% (184.3 mAh g–1) of its capacity after 100 cycles at 1C. Our results highlight a promising avenue for enhancing the electrochemical performance of LiCoO2by anisotropic surface doping with Mg2+.

Solid-state lithium-metal batteries with composite polymer electrolytes are promising for next-generation energy-storage devices. Typical synthesis strategies of preparing inorganic-polymer composite mainly focused on physical mixing of inorganic fillers with polymer or surface coating of inorganic thin films on polymer, which are hard to suppress Li-dendrite penetration. Here, we demonstrate the bulk and interface properties of powdery poly (ethylene oxide) can be modified simultaneously with highly dispersed alumina using a vapor phase infiltration approach. The chemically synthesized alumina with under-coordinated aluminum sites shows strong interaction with PEO, and therefore highly dispersed in the polymer matrix as well as on the surface of the polymer. On the lithium metal anode side, it reduces the interfacial resistance and allows Li|Li symmetric battery to cycle more than 1400 hours under 0.2 mAh/cm2. On the cathode side, it increases the electrochemical stability window of PEO up to 4.25V without compromising the charge transfer kinetics. The result shows the promise of using vapor phase infiltration as a facile one-step method to tune the properties of the polymer on a large scale for battery applications.

Bottom-up synthesis based on site-selective atomic layer deposition is a powerful atomic-scale processing approach to fabricate materials with desired functionalities. Typical selective atomic layer deposition (ALD) can be achieved using selective activation of a growth area or selective deactivation of a protected area. In this work, we explored the site selectivity based on the difference of the inherent surface reactivity between different materials and within the same materials. By sequentially applying two site-selective atomic layer deposition, the ALD Pd catalyst is spatially confined on ALD SnO2modified h-BN substrate Pd/SnO2/h-BN shows improved catalytic activity and stability due to strong metal–support interactions and spatial confinement. The results reveal that sequential site-selective ALD is a feasible and effective synthesis strategy that provides an attractive path toward designing and developing highly stable catalysts.

Abstract: The I–V characteristic of a superconductor is generally described by power-law, in which the superconductor with a high n value transfers quickly from superconducting state to the normal conducting state. With a high transport current, in the low n value area, flux flow voltage becomes lower than in the high n value area, so that the transient characteristics strongly affect its stability. Based on those properties, we propose a new hybrid conductor which is made of low temperature superconductor (LTS) and high temperature superconductor (HTS) with concentric configuration in which the HTS coat is located outside of the LTS core. According to their power-law models, the modified adiabatic and dynamic stability criteria are qualitatively obtained by taking account into not only their critical currents but also n values. As a result, the new hybrid conductors have potential applications with higher engineering current density and improved stability.