Post-crotonylation oxidation by a monooxygenase promotes acetyl-CoA synthetase degradation in Streptomyces roseosporus.

Protein post-translational modifications (PTMs) with various acyl groups play central roles in Streptomyces. But whether these acyl groups can be further modified, and the influences of these potential modifications on bacterial physiology have not been addressed. Here in Streptomyces roseosporus with rich crotonylation, a luciferase monooxygenase LimB is identified to elaborately regulate the crotonylation level, morphological development and antibiotic production by oxidation on the crotonyl groups of an acetyl-CoA synthetase Acs. This chemical modification on crotonylation leads to Acs degradation via the protease ClpP1/2 pathway and lowered intracellular crotonyl-CoA pool. Thus, we show that acyl groups after PTMs can be further modified, herein named post-PTM modification (PPM), and LimB is a PTM modifier to control the substrate protein turnover for cell development of Streptomyces. These findings expand our understanding of the complexity of chemical modifications on proteins for physiological regulation, and also suggest that PPM would be widespread.

Deciphering Electrolyte Dominated Na+ Storage Mechanisms in Hard Carbon Anodes for Sodium-Ion Batteries.

Although hard carbon (HC) demonstrates superior initial Coulombic efficiency, cycling durability, and rate capability in ether-based electrolytes compared to ester-based electrolytes for sodium-ion batteries (SIBs), the underlying mechanisms responsible for these disparities remain largely unexplored. Herein, ex situ electron paramagnetic resonance (EPR) spectra and in situ Raman spectroscopy are combined to investigate the Na storage mechanism of HC under different electrolytes. Through deconvolving the EPR signals of Na in HC, quasi-metallic-Na is successfully differentiated from adsorbed-Na. By monitoring the evolution of different Na species during the charging/discharging process, it is found that the initial adsorbed-Na in HC with ether-based electrolytes can be effectively transformed into intercalated-Na in the plateau region. However, this transformation is obstructed in ester-based electrolytes, leading to the predominant storage of Na in HC as adsorbed-Na and pore-filled-Na. Furthermore, the intercalated-Na in HC within the ether-based electrolytes contributes to the formation of a uniform, dense, and stable solid-electrolyte interphase (SEI) film and eventually enhances the electrochemical performance of HC. This work successfully deciphers the electrolyte-dominated Na+ storage mechanisms in HC and provides fundamental insights into the industrialization of HC in SIBs.

Porous Ionic Network/CNT Composite Separator as a Polysulfide Snaring Shield for High Performance Lithium-Sulfur Battery.

Lithium-sulfur (Li-S) battery features a high theoretical energy density, but the shuttle of soluble polysulfides between the two electrodes often results in a rapid capacity decay. Herein, a straightforward electrostatic adsorption strategy based on a cross-linked polyimidazolium separator as a snaring shield of polysulfides is reported, which suppresses the undesirable migration of polysulfides to the anode. The porous ionic network (PIN)-modified carbon nanotubes (CNTs) are successfully prepared and coated onto a commercial porous polypropylene membrane in a vacuum-filtration step. The favorable affinity of the imidazolium ring toward polysulfide via the polar interaction and the electrostatic effect of ions mitigates the undesirable shuttle of polysulfides in the electrolyte, improving the Li─S battery in terms of rate performance and cycling life. Compared to the reference PIN-free CNT-coated separator, the PIN/CNT-coated one has an increased initial capacity of 1.3 folds (up to 1394.8 mAh g-1 for PIN/CNT/PP-3) at 0.1 C.

Machine-learning-assisted omnidirectional bending sensor based on a cascaded asymmetric dual-core PCF sensor.

An omnidirectional bending sensor comprising cascaded asymmetric dual-core photonic crystal fibers (ADCPCFs) is designed and demonstrated experimentally. Upon cascading and splicing two ADCPCFs at a lateral rotation angle, the transmission spectrum of the sensor becomes highly dependent on the bending direction. Machine learning (ML) is employed to predict the curvature and bending orientation of the bending sensor for the first time, to the best of our knowledge. The experimental results demonstrate that the ADCPCF sensor used in combination with machine learning can predict the curvature and omnidirectional bending orientation within 360° without requiring any post-processing fabrication steps. The prediction accuracy is 99.85% with a mean absolute error (MAE) of 2.7° for bending direction measurement and 98.08% with an MAE of 0.03 m-1 for the curvature measurement. This promising strategy utilizes the global features (full spectra) in combination with machine learning to overcome the dependence of the sensor on high-quality transmission spectra, the wavelength range, and a special wavelength dip in the conventional dip tracking method. This excellent omnidirectional bending sensor has large potential for structural health monitoring, robotic arms, medical instruments, and wearable devices.

Modulation of Radical Intermediates in Rechargeable Organic Batteries.

Organic materials have been considered as promising electrodes for next-generation rechargeable batteries in view of their sustainability, structural flexibility, and potential recyclability. The radical intermediates generated during the redox process of organic electrodes have profound effect on the reversible capacity, operation voltage, rate performance, and cycling stability. However, the radicals are highly reactive and have very short lifetime during the redox of organic materials. Great efforts have been devoted to capturing and investigating the radical intermediates in organic electrodes. Herein, this review summarizes the importance, history, structures, and working principles of organic radicals in rechargeable batteries. More importantly, challenges and strategies to track and regulate the radicals in organic batteries are highlighted. Finally, further perspectives of organic radicals are proposed for the development of next-generation high-performance rechargeable organic batteries.

Ultrafast Strategy to Fabricate Sulfur Cathodes for High-Performance Lithium-Sulfur Batteries.

Based on the different dielectric properties of materials and the selective heating property of microwaves, the ultrafast (30 s) preparation of S-NiS2@SP@Bitu as a cathode material for lithium-sulfur batteries was achieved using bitumen, sulfur, Super P, and nickel naphthenate as raw materials for the first time, under microwave treatment. NiS2@SP@Bitu forms Li-N, Li-O, Li-S, and Ni-S bonds with polysulfide, which contributes to promoting the adsorption of polysulfide, reducing the precipitation and decomposition energy barrier of Li2S, and accelerating the catalytic conversion of polysulfide, as result of inhibiting the "shuttle effect" and improving the electrochemical performance. S-NiS2@SP@Bitu as the sulfur cathode material demonstrates outstanding rate performance (518.6 mAh g-1 at 4C), and stable cycling performance. The lithium-sulfur battery with a sulfur loading of 4.8 mg cm-2 shows an areal capacity of 4.6 mAh cm-2. Based on the advantages of microwave selective and rapid heating, this method creatively realized that the sulfur carrier material was prepared and sulfur was fixed in it at the same time. Therefore, this method would have implications for the preparation of sulfur cathode materials.

Precisely manipulated π-π stacking of catalytic exfoliated iron polyphthalocyanine/reduced graphene oxide hybrid via pyrolysis-free path.

Metal macrocycles with well-defined molecular structures are ideal platforms for the in-depth study of electrochemical oxygen reduction reaction (ORR). Structural integrity of metal macrocycles is vital but remain challenging since the commonly used high-temperature pyrolysis would cause severe structure damage and unidentifiable active sites. Herein, we propose a pyrolysis-free strategy to precisely manipulate the exfoliated 2D iron polyphthalocyanine (FePPc) anchored on reduced graphene oxide (rGO) via π-π stacking using facile high-energy ball milling. A delocalized electron shift caused by π-π interaction is firstly found to be the mechanism of facilitating the remarkable ORR activity of this hybrid catalyst. The optimal FePPc@rGO-HE achieves superior half-wave potential (0.90 V) than 20 % Pt/C. This study offers a new insight in designing stable and high-performance metal macrocycle catalysts with well-defined active sites.

Regeneration of NCM622 from end-of-life lithium-ion battery cathode materials.

The boom of the electric vehicle industry significantly aggravates the demand for lithium-ion batteries (LIBs), especially the ternary cathode materials, however, the majority of end-of-life (EOL) LIBs on the market are batteries utilized in customer electronics. Here, we utilized the mixed EOL LIBs from cell phones and laptops to manufacture the LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode material. A feasible, high efficiency (99.98% Co, 99.98% Ni, 99.99% Mn, and 99.99% Li), and ultra-fast leaching of EOL LIB cathodes was achieved. Thermodynamic calculations suggested that the coordination number, coordination species concentrations, and fractions have significant effects on the apparent activation energy and the equilibrium of the leaching reactions. The remanufactured NCM622 cathode material demonstrated a well-ordered layered hexagonal structure with a low Li+/Ni2+ mixing ratio, which facilitated reliable reversible capacity, low polarization, high rate capabilities (163.8 mA h g-1), and capacity retention ratio (94.3%).

Animal- and Human-Inspired Nanostructures as Supercapacitor Electrode Materials: A Review.

Human civilization has been relentlessly inspired by the nurturing lessons; nature is teaching us. From birds to airplanes and bullet trains, nature gave us a lot of perspective in aiding the progress and development of countless industries, inventions, transportation, and many more. Not only that nature inspired us in such technological advances but also, nature stimulated the advancement of micro- and nanostructures. Nature-inspired nanoarchitectures have been considered a favorable structure in electrode materials for a wide range of applications. It offers various positive attributes, especially in energy storage applications, such as the formation of hierarchical two-dimensional and three-dimensional interconnected networked structures that benefit the electrodes in terms of high surface area, high porosity and rich surface textural features, and eventually, delivering high capacity and outstanding overall material stability. In this review, we comprehensively assessed and compiled the recent advances in various nature-inspired based on animal- and human-inspired nanostructures used for supercapacitors. This comprehensive review will help researchers to accommodate nature-inspired nanostructures in industrializing energy storage and many other applications.

N, S-Coordinated Co Single Atomic Catalyst Boosting Adsorption and Conversion of Lithium Polysulfides for Lithium-Sulfur Batteries.

Boosting reversible solid-liquid phase transformation from lithium polysulfides to Li2 S and suppressing the shuttling of lithium polysulfides from the cathode to the lithium anode are critical challenges in lithium-sulfur batteries. Here, sulfiphilic single atomic cobalt implanted in lithiophilic heteroatoms-dopped carbon (SACo@HC) matrix with a CoN3 S structure for high-performance lithium-sulfur batteries is reported. Density functional theory calculation and in situ experiments demonstrate that the optimal CoN3 S structure in SACo@HC can effectively improve the adsorption and redox conversion efficiency of lithium polysulfides. Consequently, the S-SACo@HC composite with sulfur loading of 80 wt% delivers a high capacity of 1425.1 mAh g-1 at 0.05 C and outstanding rate performance with 745.9 mAh g-1 at 4 C. Furthermore, a capacity of 680.8 mAh g-1 at 0.5 C with a low electrolyte/sulfur ratio (6 µL mg-1 ) can be achieved even after 300 cycles. With the harsh conditions of lean electrolyte (E/S = 4 µL mg-1 ) and high sulfur loading (5.4 mg cm-2 ), a superior area capacity of 5.8 mAh cm-2 can be obtained. This work contributes to building a profound understanding of the adsorption and interface engineering of lithium polysulfides and provides ideas to tackle the long-standing polysulfide shuttle problem of lithium-sulfur batteries.

Unraveling the Role of Aromatic Ring Size in Tuning the Electrochemical Performance of Small-Molecule Imide Cathodes for Lithium-Ion Batteries.

Organic electrode materials have the typical advantages of flexibility, low cost, abundant resources, and recyclability. However, it is challenging to simultaneously optimize the specific capacity, rate capability, and cycling stability. Radicals are inevitable intermediates that critically determine the redox activity and stability during the electrochemical reaction of organic electrodes. Herein, we select a series of aromatic imides, including pyromellitic diimide (PMDI), 1,4,5,8-naphthalenediimide (NDI), and 3,4,9,10-perylenetetracarboxylicdiimide (PTCDI), which contain different extending π-conjugated aromatic rings, to study the relationship between their electrochemical performance and the size of the aromatic ring. The results show that regulating the aromatic ring size of imide molecules could finely tune the energies of the lowest unoccupied molecular orbital (LUMO), thus optimizing the redox potential. The rate performance of PMDI, NDI, and PTCDI increases with the aromatic ring size, which is consistent with the decrease in the LUMO-HOMO gap of these imide molecules. DFT calculations and experiments reveal that the redox of imide radicals dominates the charge/discharge processes. Also, extending the aromatic rings could more effectively disperse the spin electron density and improve the stability of imide radicals, contributing to the enhanced cycling stability of these imide electrodes. Hence, aromatic ring size regulation is a simple and novel approach to simultaneously enhance the capacity, rate capability, and cycling stability of organic electrodes for high-performance lithium-ion batteries.

Ternary Transition Metal Sulfide as High Real Energy Cathode for Lithium-Sulfur Pouch Cell Under Lean Electrolyte Conditions.

Fabrication of a highly porous sulfur host and using excess electrolyte is a common strategy to enhance sulfur utilization. However, flooded electrolyte limits the practical energy density of Li-S pouch cells. In this study, a novel Fe0.34 Co0.33 Ni0.33 S2 (FCN) is proposed as host for sulfur to realize Ah-level Li-S full cells demonstrating excellent electrochemical performances under 2 µL mg-1 lean electrolyte conditions. Moreover, Kelvin probe force microscopy shows that the FCN surface contains positive charge with a potential of ≈70 mV, improving the binding of polysulfides through Lewis acid base interaction. In particular, the FCN@S possesses inherent electrochemical activity of simultaneous anionic and cationic redox for lithium storage in the voltage window of 1.8-2.1 V, which additionally contributes to the specific capacity. Due to the low carbon content (≈10 wt%), the sulfur loading is as high as ≈6 mg cm-2 , approaching an outstanding energy density of 394.9 and 267.2 Wh kg-1 at the current density of 1.5 and 4 mA cm-2 , respectively. Moreover, after 60 cycles at 1.5 mA cm-2 , the pouch cell still retains an energy of 300.2 Wh kg-1 . This study represents a milestone in the practical applications of high-energy Li-S batteries.

Phosphorus containing layered quadruple hydroxide electrode materials on lab waste recycled flexible current collector.

From environmental waste to energy storage, waste boxes converted into conductive electrodes to further grow active materials has been an interesting way of upcycling. In this study, we transformed waste boxes of KIMTECH Kimwipes® into conductive f-MWCNTs light and flexible substrate (LFS) as current collectors. Then, undoped and P-doped active materials consisting of layered quadruple hydroxides (LQH) was successfully grown on the conductive f-MWCNTs/LFS. Specifically, P-doped f-MWCNTs/LQH demonstrates 1.8 times the capacitance of an undoped f-MWCNTs/LQH. Such conversion of waste boxes not only offers a useful way of reusing waste papers which commonly ends in landfills, but the inexpensive method also offers an extreme way of cutting cost in developing conductive substrates. Also, the effective strategy of synthesizing active materials on the conductive f-MWCNTs/LFS paves its way as potential cheap electrodes of the future generation.

Single-ring hollow-core anti-resonant fiber with a record low loss (4.3†dB/km) for high-power laser delivery at 1†µm.

We report a 7-tube single-ring hollow-core anti-resonant fiber (SR-ARF) with a record low transmission loss of 4.3 dB/km @1080 nm, which is almost half of the current lowest loss record of an SR-ARF (7.7 dB/km @750 nm). The 7-tube SR-ARF has a large core diameter of 43 µm and a wide low-loss transmission window exceeding 270 nm for the 3-dB bandwidth. Moreover, it exhibits an excellent beam quality with an M2 factor of 1.05 after 10-m-long transmission. The robust single-mode operation, ultralow loss, and wide bandwidth make the fiber an ideal candidate for short-distance Yb and Nd:YAG high-power laser delivery.

Extra Sodiation Sites in Hard Carbon for High Performance Sodium Ion Batteries.

Hard carbons are promising anodes for sodium-ion batteries (SIBs). However, the low practical capacity from limited sodiation sites impedes their applications. Herein, ultrahigh concentration of pyridine N (≈7.9%) is introduced inside hard carbon, considering that pyridine N may provide extra sodium storage sites with stable CN• and CC• radicals during cycling. To expose more radical sites for sodium storage, a 3D structure with a multistage pore structure is constructed through NH3 release during the pyrolyzation process. As expected, the hard carbon with extra sodiation sites exhibits an impressively high capacity of 434 mA h g-1 at 20 mA g-1 , superior rate performance of 238 mA h g-1 at a current density of 5 A g-1 and a high-capacity retention of 98.7% after 5000 cycles. The radicals induced Na-adsorption mechanism was further explored through ex situ electron paramagnetic resonance technology, in situ Raman technology and density functional theory calculations. The results reveal that the extra sodiation sites come from the electrostatic interaction at low potentials. This work constructs a sodium ions storage model of extra radicals and provides an extended strategy to improve the electrochemical performance of SIBs anode materials.

Coupling a Three-Dimensional Nanopillar and Robust Film to Guide Li-Ion Flux for Dendrite-Free Lithium Metal Anodes.

Lithium metal batteries with high theoretical capacity critically suffer from low cycling stability and safety issues mostly due to lithium dendrites. Regulating the Li-ion conduction and Li deposition is essential to achieve dendritic-free Li metal anodes. Herein, a synergistic strategy that combines a 3D nanocopper layer and a robust polymer protective layer is proposed. The 3D nanocopper layer in situ formed on the Li surface could achieve a uniform electric field distribution and contribute to reducing the nucleation barrier for Li deposition and refining the grain size of Li crystallites. Meanwhile, the Li-Nafion film with high Li-ion conductivity and good flexibility was used as a protective layer to provide homogeneous ion distribution and adapt to the volume change during the Li deposition. Consequently, the NCuLi∥LiCoO2 full cells exhibited outstanding cycling stability (a capacity retention of 90% over 500 cycles). Our results indicate that the synergistic control of Li-ion conduction and Li deposition is a promising method to achieve dendritic-free Li metal anodes.

Dilute Aqueous-Aprotic Hybrid Electrolyte Enabling a Wide Electrochemical Window through Solvation Structure Engineering.

The application of superconcentrated aqueous electrolytes has shown great potential in developing high-voltage electrochemical double-layer capacitors (EDLCs). However, the broadening of the electrochemical window of such superconcentrated electrolytes is at the expense of their high cost, low ionic conductivity, high density, and narrow operating temperature range. Herein, the electrochemical window of water (>3 V) at low salt concentration (3 m) is expanded by using an aprotic solvent, i.e., trimethyl phosphate (TMP), to regulate the solvation structure of the electrolyte. Benefiting from the low salt concentration, such electrolyte is simultaneously featured with high ionic conductivity, low density, and wide temperature compatibility. Based on the dilute hybrid electrolyte, EDLCs constructed by using porous graphene electrodes are able to operate within an enlarged voltage range of 0-2.4 V at a wide range of temperatures from -20 to 60 °C. They also present excellent rate capability and cycle stability, i.e., 83% capacitance retention after 100 000 cycles. Density functional theory calculations verify that TMP induces a significant electronic modulation for the bonding environment of the electrolyte. This enables the stronger binding of Na+ -H2 O with freely migrating TMP to expand the voltage window to exceed the potential limitation of aqueous electrolytes.

Redox of naphthalenediimide radicals in a 3D polyimide for stable Li-ion batteries.

A 3D polyimide is designed as an organic cathode for Li-ion batteries. Detailed characterization and DFT simulations demonstrate that the 3D polyimide undergoes the redox of naphthalenediimide radicals and the rigidity effect of the 3D structure contributes to the stability of the radical intermediates for high-performance organic batteries.

Large-mode-area all-solid anti-resonant fiber with single-mode operation for high-power fiber lasers.

We investigate the feasibility of applying an anti-resonant guiding mechanism in an all-solid anti-resonant fiber (AS-ARF) to achieve a large mode area (LMA) and single mode for high-power fiber laser applications. A novel, to the best of our knowledge, AS-ARF with nonuniform rods is proposed to enhance the single-mode property and enlarge the mode area. The numerical results show that the core diameter can expand to 57, 80, and 100 µm at the wavelengths of 1.064, 1.55, and 2 µm, respectively. The loss ratio of the lowest loss of higher-order modes to the loss of the fundamental mode can exceed 1000, 550, and 860 at the wavelength of 1.064, 1.55, and 2 µm; thus, robust single-mode operation can be ensured. Besides, the fiber can also be adapted to bent condition under certain heat load. These indicate that the proposed AS-ARF with nonuniform rods is a great candidate as an LMA fiber for high-power fiber lasers.

Development of vertically aligned trimetallic Mg-Ni-Co oxide grass-like nanostructure for high-performance energy storage applications.

Direct growth of nanostructured trimetallic oxide on substrate is considered as one of the promising electrode fabrication for high-performance hybrid supercapacitors. Herein, binder-free one-dimensional grass-like nanostructure was constructed on nickel foam by using electrodeposition approach. The admirable enhancement in rate capability was observed by the substitution of Mg and Ni in cobalt oxide crystallite. The prepared nickel cobalt oxide (NCO) and cobalt oxide (CO) electrode exhibited a rate capability of 57% and 58% (2 to 10 A g-1) respectively. Interestingly, the rate capability was increased to 87% by the substitution of Mg and Ni simultaneously. The novel vertically aligned trimetallic Mg-Ni-Co oxide (MNCO) grass-like nanostructure electrode exhibited a high specific capacity of 846 C g-1 at 2 A g-1, retained 97.3% specific capacity and showed an outstanding coulombic efficiency of 99% after 10,000 charge-discharge cycles. Moreover, we assembled hybrid supercapacitor (HSC) device for practical applications by using MNCO and activated carbon (AC) as the positive and negative electrode materials, respectively. HSC device exhibited a high specific capacity of 144 C g-1 at 0.5 A g-1. The high energy density of 31.5 Wh kg-1 and the power density of 7.99 kW kg-1 were achieved. All these interesting and attractive results demonstrate the significance of the vertically aligned electrode material towards practical applications.