Molecular Engineering to Regulate the Pseudo-Graphitic Structure of Hard Carbon for Superior Sodium Energy Storage.

Resin-derived hard carbons have shown great advantages in serving as promising anode materials for sodium-ion batteries due to their flexible microstructure tunability. However, it remains a daunting challenge to rationally regulate the pseudo-graphitic crystallite and defect of hard carbon toward advanced sodium storage performance. Herein, a molecular engineering strategy is demonstrated to modulate the cross-linking degree of phenolic resin and thus optimize the microstructure of hard carbon. Remarkably, the resorcinol endows resin with a moderate cross-linking degree, which can finely tune the pseudo-graphitic structure with enlarged interlayer spacing and restricted surface defects. As a consequence, the optimal hard carbon delivers a notable reversible capacity of 334.3 mAh g-1 at 0.02 A g-1, a high initial Coulombic efficiency of 82.1%, superior rate performance of 103.7 mAh g-1 at 2 A g-1, and excellent cycling durability over 5000 cycles. Furthermore, kinetic analysis and in situ Raman spectroscopy are performed to reveal the electrochemical advantage and sodium storage mechanism. This study fundamentally sheds light on the molecular design of resin-based hard carbons to advance sodium energy for scale-up applications.

Resolving Deactivation of Low-Spin Fe Sites by Redistributing Electron Density toward High-Energy Sodium Storage.

Prussian blue (PB) has been an emerging class of cathode material for sodium-ion batteries due to its low cost and high theoretical capacity. However, their working voltage and capacity are substantially restricted due to the deactivation of low-spin Fe sites. Herein, we demonstrate a universal strategy to activate the low-spin Fe sites of PB by hybridizing them with the π-π conjugated electronic conductors. The redistribution of electron density between π-π conjugated conductors and PB effectively promotes the participation of low-spin Fe sites in sodium storage. Consequently, the low-spin Fe-induced plateau is greatly aroused, resulting in a high specific capacity of 148.4 mAh g-1 and remarkable energy density of 444.2 Wh kg-1. In addition, the excellent structural stability enables superior cycling stability over 2500 cycles and outstanding rate performance. The work will provide fundamental insight into activating the low-spin Fe sites of PB for advanced battery technologies.

TiO2@TiO2-xHx core-shell nanoparticle film/Si heterojunction for ultrahigh detectivity and sensitivity broadband photodetector.

A simple hydrogenation treatment is used to synthesize unique oxygen-deficient TiO2 with a core/shell structure (TiO2@TiO2-xHx), superior to the high H2-pressure process (under 20 bar for five days). It is demonstrated that oxygen-deficient TiO2 nanoparticle film/Si heterojunction possesses improved photoresponse performance compared to the untreated TiO2 nanoparticle film/Si heterojunction. Particularly, under 900 nm of 0.5 µW cm-2, the oxygen-deficient TiO2 nanoparticle film (TiO2@TiO2-xHx core-shell nanoparticle film)/Si heterojunction shows high responsivity (R) of 336 A W-1, prominent sensitivity (S) of 1.3 × 107 cm2 W-1, accompanied with a fast rise and decay time of 6 and 5 ms, respectively. Significantly, the detectivity (D*) of the photodetector is up to 1.17 × 1014 cm Hz1/2 W-1, which is better than that reported in metal oxide nanomaterials/Si heterojunction photodetectors, and is 4-5 orders of magnitude higher than some 2D nanosheets/Si heterojunctions of 109-1010 cm Hz1/2 W-1, indicating the excellent ability to detect weak signals. The oxygen vacancies generated in amorphous shell TiO2-xHx make the Fermi level of TiO2-x shift near the conduction band minimum and can lead to reduced dark current. The high absorption and reduced dark current of the heterojunction ensure excellent photoresponse properties of oxygen-deficient TiO2 nanoparticle film/Si heterojunction. The H-reduced oxygen-deficient amorphous shell may be an excellent candidate to enhance the photoresponse performance of metal oxide/Si heterojunction.

Green Phytic Acid-Assisted Synthesis of LiMn1-xFexPO4/C Cathodes for High-Performance Lithium-Ion Batteries.

As a promising cathode material, olivine-structured LiMnPO4 holds enormous potential for lithium-ion batteries. Herein, we demonstrate a green biomass-derived phytic-acid-assisted method to synthesize a series of LiMn1-xFexPO4/C composites. The effect of Fe doping on the crystal structure and morphology of LiMnPO4 particles is investigated. It is revealed that the optimal Fe doping amount of x = 0.2 enables a substantial enhancement of interfacial charge transfer ability and Li+ ion diffusion kinetics. Consequently, a large reversible capacity output of 146 mAh g-1 at 0.05 C and a high rate capacity of 77 mAh g-1 at 2 C were acquired by the as-optimized LiMn0.8Fe0.2PO4/C cathode. Moreover, the LiMn0.8Fe0.2PO4/C delivered a specific capacity of 68 mAh g-1 at 2 C after 500 cycles, with a capacity retention of 88.4%. This work will unveil a green synthesis route for advancing phosphate cathode materials toward practical implementation.

Achieving high-capacity and durable sodium storage by constructing a binder-free nanotube array architecture of iron phosphide/carbon.

The conversion-type anode material of iron phosphide (FeP) promises enormous prospects for Na-ion battery technology due to its high theoretical capacity and cost-effectiveness. However, the poor reaction kinetics and large volume expansion of FeP significantly degrade the sodium storage, which remains a daunting challenge. Herein, we demonstrate a binder-free nanotube array architecture constructed by FeP@C hybrid on carbon cloth as advanced anodes to achieve fast and stable sodium storage. The nanotubular structure functions in multiple roles of providing short electron/ion transport distances, smooth electrolyte diffusion channels, and abundant active sites. The carbon layer could not only pave high-speed pathways for electron conductance but also cushion the volume change of FeP. Benefiting from these structural virtues, the FeP@C anode receives a high reversible capacity of 881.7 mAh/g at 0.1 A/g, along with a high initial Coulombic efficiency of 90% and excellent rate capability and cyclability in half and full cells. Moreover, the sodium energy reaction kinetics and mechanism of FeP@C are systematically studied. The present work offers a rational design and construction of high-capacity anode materials for high-energy-density Na-ion batteries.

Boosting large-current-density water oxidation activity and stability by phytic acid-assisted rapid electrochemical corrosion.

Corrosion engineering is an efficient strategy to achieve durable oxygen evolution reaction (OER) catalysts at high current densities beyond 500 mA cm-2. However, the spontaneous electrochemical corrosion has a slow reaction rate, and most of them need to add large amounts of salts (such as NaCl) to accelerate the corrosion process. In this report, a novel and effective phytic acid (PA)-assisted in situ electrochemical corrosion strategy is demonstrated to accelerate the the corrosion process and form bimetallic active catalysts to show excellent OER performance at large current densities. In situ rapid electrochemical corrosion of nickel foam substrate and PA ligands etching realize localized high concentrations of Ni and Fe ions. High concentrations of metal ions will combine with hydroxyl to effectively form defects-enriched NiFe layered double hydroxides porous nanosheets tightly anchoring on the underneath substrate. Remarkably, the activated electrode exhibits excellent OER catalytic activities with ultralow overpotentials of 289 and 315 mV to reach high current densities of 500 and 1000 mA cm-2, respectively. When coupled with Ni-Mo-N hydrogen evolution reaction catalysts, the two-electrode cell merely requires 1.87 V to deliver 1000 mA cm-2. The ligands-assisted rapid electrochemical corrosion strategy provides a fresh perspective for facile, cost-effective, and scale-up production of superior OER catalysts at large current densities.

Biomass-Derived Hard Carbon with Interlayer Spacing Optimization toward Ultrastable Na-Ion Storage.

Hard carbons as a kind of nongraphitized amorphous carbon have been recognized as potential anode materials for sodium-ion batteries (SIBs) due to its large interlayer spacing. However, the issues in terms of onerous synthetic procedure and elusive working mechanism remains critical bottlenecks for practical implement. Herein, we report a facile production of tubular hard carbon through direct carbonization of platanus flosses (FHC) for the first time. Through optimizing the pyrolysis temperatures, the FHC obtained at 1300 °C possesses a key balance between the interlayer spacing and surface area, which can maintain the substantial active sites as well as reduce the irreversible sodium storage. Accordingly, it can deliver a reversible capacity of 324.6 mAh g-1 with a high initial Coulombic efficiency of 80%, superb rate property of 107.2 mAh g-1 at 2 A g-1, and long operating stability over 1000 cycles. Furthermore, the in situ Raman spectroscopic studies certify that sodium ions are stored in FHC following the "adsorption-insertion" mechanism. Our study could provide a promising route for large-scale development of the biomass-derived carbonaceous anodes for high-performance SIBs.

Recycling spent masks to fabricate flexible hard carbon anode toward advanced sodium energy storage.

The massive discard of spent masks during the COVID-19 pandemic imposes great environmental anxiety to the human society, which calls for a reliable and sustainable outlet to mitigate this issue. In this work, we demonstrate a green design strategy of recycling the spent masks to fabricate hard carbon fabrics toward high-efficient sodium energy storage. After a simple carbonization treatment, flexible hard carbon fabrics composed of interwoven microtubular fibers are obtained. When serving as binder-free anodes of sodium-ion batteries, a large Na-ion storage capacity of 280 mAh g-1 is achieved for the optimized sample. More impressively, the flexible anode exhibits an initial coulombic efficiency of as high as 86% and excellent rate/cycling performance. The real-life practice of the flexible hard carbon is realized in the full-cells. The present study affords an enlightening approach for the recycling fabrication of high value-added hard carbon materials from the spent masks for advanced sodium energy storage.

Ultrafine MoS2 Nanosheets Vertically Patterned on Graphene for High-Efficient Li-Ion and Na-Ion Storage.

Hierarchically two-dimensional (2D) heteroarchitecture with ultrafine MoS2 nanosheets vertically patterned on graphene is developed by using a facile solvothermal method. It is revealed that the strong interfacial interaction between acidic Mo precursors and graphene oxides allows for uniform and tight alignment of edge-oriented MoS2 nanosheets on planar graphene. The unique sheet-on-sheet architecture is of grand advantage in synergistically utilizing the highly conductive graphene and the electroactive MoS2, thus rendering boosted reaction kinetics and robust structural integrity for energy storage. Consequently, the heterostructured MoS2@graphene exhibits impressive Li/Na-ion storage properties, including high-capacity delivery and superior rate/cycling capability. The present study will provide a positive impetus on rational design of 2D metal sulfide/graphene composites as advanced electrode materials for high-efficient alkali-metal ion storage.

Building Ohmic Contact Interfaces toward Ultrastable Zn Metal Anodes.

Zn metal holds grand promise as the anodes of aqueous batteries for grid-scale energy storage. However, the rampant zinc dendrite growth and severe surface side reactions significantly impede the commercial implementation. Herein, a universal Zn-metal oxide Ohmic contact interface model is demonstrated for effectively improving Zn plating/stripping reversibility. The high work function difference between Zn and metal oxides enables the building of an interfacial anti-blocking layer for dendrite-free Zn deposition. Moreover, the metal oxide layer can function as a physical barrier to suppress the pernicious side reactions. Consequently, the proof-of-concept CeO2 -modified Zn anode delivers ultrastable durability of over 1300 h at 0.5-5 mA cm-2 and improved Coulombic efficiency, the feasibility of which is also evidenced in MoS2 //Zn full cells. This study enriches the fundamental comprehension of Ohmic contact interfaces on the Zn deposition, which may shed light on the development of other metal battery anodes.

A new cerebroside from cordyceps militaris with anti-PTP1B activity.

Cordyceps militaris (L.) Link (C. militaris) has been used as a folk medicine for treatment of various diseases in China and some other countries. Recent evidence suggests that aqueous extracts of C. militaris have hypoglycemic activity. So the aim of this study was to isolate and characterize compounds with aiti-PTP1B (protein tyrosine phosphatase 1B) activity from C. militaris. As a result, cordycerebroside B (1) together with other three known cerebrosides (2-4) and a disaccharide (5) were isolated by silica gel column chromatography and semi-preparative high performance liquid chromatography (HPLC) and then elucidated on the basis of 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS) and chemical method. Among of which, cordycerebroside B was a new compound and isolated from C. militaris for the first time. The results of the activity assays demonstrated that all these four cerebrosides (compounds 1-4) showed marked inhibition activity against PTP1B with IC50 values of 4.68 ±â€¯0.18, 16.93 ±â€¯1.08, 10.43 ±â€¯0.64 and 18.92 ±â€¯1.65 µM. All the compounds had no discernible cytotoxicity for Rat pheochromocytoma (PC12 cells). These findings suggested that C. militaris or its cerebrosides may be considered as potential useful therapeutic agents for type 2 diabetes.

Chronic Caffeine Treatment Protects Against α-Synucleinopathy by Reestablishing Autophagy Activity in the Mouse Striatum.

Despite converging epidemiological evidence for the inverse relationship of regular caffeine consumption and risk of developing Parkinson's disease (PD) with animal studies demonstrating protective effect of caffeine in various neurotoxin models of PD, whether caffeine can protect against mutant α-synuclein (α-Syn) A53T-induced neurotoxicity in intact animals has not been examined. Here, we determined the effect of chronic caffeine treatment using the α-Syn fibril model of PD by intra-striatal injection of preformed A53T α-Syn fibrils. We demonstrated that chronic caffeine treatment blunted a cascade of pathological events leading to α-synucleinopathy, including pSer129α-Syn-rich aggregates, apoptotic neuronal cell death, microglia, and astroglia reactivation. Importantly, chronic caffeine treatment did not affect autophagy processes in the normal striatum, but selectively reversed α-Syn-induced defects in macroautophagy (by enhancing microtubule-associated protein 1 light chain 3, and reducing the receptor protein sequestosome 1, SQSTM1/p62) and chaperone-mediated autophagy (CMA, by enhancing LAMP2A). These findings support that caffeine-a strongly protective environment factor as suggested by epidemiological evidence-may represent a novel pharmacological therapy for PD by targeting autophagy pathway.

Impact of Cold Exposure on the Reproductive Function in Female Rats.

Female reproductive system diseases caused by exposure to a cold environment are widely considered as important human health challenges. Although the projection of female reproduction in cold temperature has been studied, a holistic view on the probable effects of cold exposure on the functions of the female reproductive system has not been achieved. Our aim was to evaluate the effects of cold exposure to the functions of the ovary and uterus in female rats. For this purpose, female rats were randomly grouped as follows: (1) the cold group was exposed to -10°C, 4 h per day for 2 weeks, and (2) the normal temperature (23 ± 1°C) group was used as control. Alterations were observed in different parameters, including body weight gain, organ coefficients, estrus cycle, and pathology of the cold-exposed female rats. Similarly, the serum reproductive hormones and mRNA expression were evaluated. Cold exposure induced estrus cycle irregularity and some alterations in the morphology of the ovary. Cold exposure impairs the function of the ovary probably by changing the level of serum LH and increasing LHR expression. Cold exposure induced a significant reduction of uterine epithelium height. Cold exposure causes alterations in the morphology of the uterus probably because of the effect of progesterone, the increase in the PR level, and the decrease in the ER level.

Pharmacological Blockade of Adenosine A2A but Not A1 Receptors Enhances Goal-Directed Valuation in Satiety-Based Instrumental Behavior.

The balance and smooth shift between flexible, goal-directed behaviors and repetitive, habitual actions are critical to optimal performance of behavioral tasks. The striatum plays an essential role in control of goal-directed versus habitual behaviors through a rich interplay of the numerous neurotransmitters and neuromodulators to modify the input, processing and output functions of the striatum. The adenosine receptors (namely A2AR and A1R), with their high expression pattern in the striatum and abilities to interact and integrate dopamine, glutamate and cannabinoid signals in the striatum, may represent novel therapeutic targets for modulating instrumental behavior. In this study, we examined the effects of pharmacological blockade of the A2ARs and A1Rs on goal-directed versus habitual behaviors in different information processing phases of instrumental learning using a satiety-based instrumental behavior procedure. We found that A2AR antagonist acts at the coding, consolidation and expression phases of instrumental learning to modulate animals' sensitivity to goal-directed valuation without modifying action-outcome contingency. However, pharmacological blockade and genetic knockout of A1Rs did not affect acquisition or sensitivity to goal-valuation of instrumental behavior. These findings provide pharmacological evidence for a potential therapeutic strategy to control abnormal instrumental behaviors associated with drug addiction and obsessive-compulsive disorder by targeting the A2AR.