UV-Permeable 3D Li Anodes for In Situ Fabrication of Interface-Gapless Flexible Solid-State Lithium Metal Batteries.

Flexible solid-state lithium metal batteries (SSLMBs) are highly desirable for future wearable electronics because of their high energy density and safety. However, flexible SSLMBs face serious challenges not only in regulating the Li plating/stripping behaviors but also in enabling the mechanical flexibility of the cell. Both challenges are largely associated with the interfacial gaps between the solid electrolytes and the electrodes. Here, a UV-permeable and flexible composited Li metal anode (UVp-Li), which possesses a unique light-penetrating interwoven structure similar to textiles is reported. UVp-Li allows one-step bonding of the cathode, anode, and solid electrolyte via an in situ UV-initiated polymerization method to achieve the gapless SSLMBs. The gapless structure not only effectively stabilizes the plating/stripping of Li metal during cycling, but also ensures the integrity of the cell during mechanical bending. UVp-Li symmetric cell presents a stable cycling over 1000 h at 0.5 mA cm-2. LiFePO4||UVp-Li full cells (areal capacity ranging from 0.5 to 3 mAh cm-2) show outstanding capacity retention of over 84% after 500 charge/discharge cycles at room temperature. Large pouch cells using high-loading cathodes maintain stable electrochemical performance during 1000 times of dynamic bending.

A Freestanding, Dissolution- and Diffusion-Limiting, Flexible Sulfur Electrode Enables High Specific Capacity at High Mass Loading.

The acquisition of stable and high-areal-capacity S cathodes over 10 mA h cm-2 is a critical and indispensable step to realize the high energy density configuration. However, increasing the areal capacity of S cathodes often deteriorates the specific capacity and stability due to the aggravated dissolution of S and diffusion of solvable polysulfides in the thick electrode. Herein, the design of a freestanding composite cathode that leverages 3D covalent binding sites and chemical adsorption environment to offer dissolution-limiting and diffusion-blocking functions of S species is reported. By employing this architecture, the coin cell exhibits excellent cycling stability and an exceptional specific capacity of 1444.3 mA h g-1 (13 mA h cm-2), and the pouch cell configuration manifests a noteworthy areal capacity exceeding 11 mA h cm-2. This performance is coupled with excellent flexibility, demonstrated through consecutive bending cycle tests, even at a sulfur loading of 9.00 mg cm-2. This study lays the foundation for the development of flexible Li-S batteries with increased loading capacities and exceptional performance.

Laser-Ablated Red Phosphorus on Carbon Nanotube Film for Accelerating Polysulfide Conversion toward High-Performance and Flexible Lithium-Sulfur Batteries.

The use of a conducting interlayer between separator and cathode is one of the most promising methods to trap lithium polysulfides (LiPSs) for enhancing the performance of lithium-sulfur (Li-S) batteries. Red phosphorus nanoparticles (RPEN )-coated carbon nanotube (CNT) film (RPEN @CF) is reported herein as a novel interlayer for Li-S batteries, which shows strong chemisorption of LiPSs, good flexibility, and excellent electric conductivity. A pulsed laser ablation method is engaged for the ultrafast production of RPEN of uniform morphology, which are deposited on the CNT film by a direct spinning method. The RPEN @CF interlayer provides pathways for effective Li+ and electron transfer and strong chemical interaction with LiPSs. The S/RPEN @CF electrode shows a superior specific capacity of 782.3 mAh g-1 (3 C-rate) and good cycling performances (769.5 mAh g-1 after 500 cycles at 1 C-rate). Density functional theory calculations reveal that the morphology and dispersibility of RPEN are crucial in enhancing Li+ and electron transfer kinetics and effective trap of LiPSs. This work demonstrates the possibility of using the RPEN @CF interlayer for the enhanced electrochemical performances of Li-S batteries and other flexible energy storage devices.

Three-Dimensional Laser-Assisted Patterning of Blue-Emissive Metal Halide Perovskite Nanocrystals inside a Glass with Switchable Photoluminescence.

The high-precision patterning of metal halide perovskites (MHPs) is of paramount importance for their device application. Here, we demonstrate the femtosecond (fs)-laser-assisted formation of three-dimensional MHP nanocrystal (NC) patterns with strong blue photoluminescence (PL) inside an oxide glass. Our strategy enables the crystallization and erasing of CsPb(Cl/Br)3 NCs inside a glass localized around the laser focal area through a combination of fs laser irradiation and thermal treatment processes. These recoverable patterns exhibit a switchable PL associated with the laser-induced defect and the thermal healing of MHP NCs that are benefits from the soft ionic crystal structure and low formation energy of the MHPs. Due to the high stability offered by the protection of the oxide glass matrix, the laser printing of fine-structured MHP micropatterns can be repeated over multiple cycles with a high robustness compared with their colloidal process counterparts. Our results demonstrate a simple strategy for creating emissive patterns inside a stable and transparent solid matrix that could be promising for applications including information storage, three-dimensional displays, anticounterfeit labels, and information security protection.

An Ultrabroadband Mid-Infrared Pulsed Optical Switch Employing Solution-Processed Bismuth Oxyselenide.

Pulsed lasers operating in the mid-infrared (3-25 µm) are increasingly becoming the light source of choice for a wide range of industrial and scientific applications such as spectroscopy, biomedical research, sensing, imaging, and communication. Up to now, one of the factors limiting the mid-infrared pulsed lasers is the lack of optical switch with a capability of pulse generation, especially for those with wideband response. Here, a semiconductor material of bismuth oxyselenide (Bi2 O2 Se) with a facile processibility, constituting an ultrabroadband saturable absorber for the mid-infrared (actually from the near-infrared to mid-infrared: 0.8-5.0 µm) is exhibited. Significantly, it is found that the optical response is associated with a strong nonlinear character, showing picosecond response time and response amplitude up to ≈330.1% at 5.0 µm. Combined with facile processibility and low cost, these solution-processed Bi2 O2 Se materials may offer a scalable and printable mid-infrared optical switch to open up the long-sought parameter space which is crucial for the exploitation of compact and high-performance mid-infrared pulsed laser sources.

Reverse Saturable Absorption Induced by Phonon-Assisted Anti-Stokes Processes.

In materials showing reverse saturable absorption (RSA), optical transmittance decreases at intense laser irradiation. One approach to application of these materials is to protect the sensors or human eyes from laser damage. To date, research has mainly concentrated on thin films and suspensions of graphite and its nanostructure (including nanotubes, graphene, and graphene oxides), which are mainly used as an optical limiter for nanosecond laser pulses. Moreover, thin individual pieces of semiconductor usually exhibit increased transmittance due to saturable absorption when the laser energy (Elaser ) is higher than the band gap (EB ). Here, it is shown that indirect gap semiconductor WSe2 exhibits high RSA on exposure to a femtosecond laser under Elaser > EB near band gap excitation, which is attributed to the longitudinal optical phonon-assisted anti-Stokes transition by the annihilation of phonons and the absorption of photons. An optical limiting threshold (≈21.6 mJ cm-2 ) lower than those reported for other optical-limiting materials currently for femtosecond laser at 800 nm is observed.

[A new flavonoid glycoside from leaves of Eucalyptus robusta].

A new flavonoid glycoside, (-)-2S-8-methyl-5,7,4'-trihydroxyflavanone-7-O-ß-D-glucopyranoside (1), along with five known ones, quercetin-3-O-(2"-galloyl)-α-L-arabinoside (2), kaempferol-3-O-α-L-arabinoside (3), guaijaverin (4), trifolin (5) and hyperin (6), was isolated from the leaves of Eucalyptus robusta. Their structures with absolute configurations were elucidated by NMR, HR-ESI-MS, CD spectra data and physicochemical methods. In addition, 2-6 were isolated from E. robusta for the first time.

Five new acylphloroglucinol glycosides from the leaves of Eucalyptus robusta.

Five new acylphloroglucinol glycosides, robustasides A-E (1-5), together with a known one (6), were isolated from the leaves of Eucalyptus robusta. The structures were elucidated on the basis of extensive spectroscopic and spectrometric analysis and chemical evidence. The absolute configuration of 1 was further determined by quantum chemical CD calculation.

Two new euglobals from the leaves of Eucalyptus robusta.

Two new euglobals, R1 (1) and R2 (2), together with eight known euglobals (3-10) were isolated from the leaves of Eucalyptus robusta. Their structures were established by means of spectroscopic analysis and single-crystal X-ray diffraction. Euglobal R1 (1) represents a new skeleton of formyl-isovaleryl phloroglucinol-coupled ß-phellandrene.