In Situ Constructing Ultrastable Mechanical Integrity of Single-Crystalline LiNi0.9 Co0.05 Mn0.05 O2 Cathode by Interior and Exterior Decoration Strategy.

Planar gliding along with anisotropic lattice strain of single-crystalline nickel-rich cathodes (SCNRC) at highly delithiated states will induce severe delamination cracking that seriously deteriorates LIBs' cyclability. To address these issues, a novel lattice-matched MgTiO3 (MTO) layer, which exhibits same lattice structure as Ni-rich cathodes, is rationally constructed on single-crystalline LiNi0.9 Co0.05 Mn0.05 O2 (SC90) for ultrastable mechanical integrity. Intensive in/ex situ characterizations combined with theoretical calculations and finite element analysis suggest that the uniform MTO coating layer prevents direct contact between SC90 and organic electrolytes and enables rapid Li-ion diffusion with depressed Li-deficiency, thereby stabilizing the interfacial structure and accommodating the mechanical stress of SC90. More importantly, a superstructure is simultaneously formed in SC90, which can effectively alleviate the anisotropic lattice changes and decrease cation mobility during successive high-voltage de/intercalation processes. Therefore, the as-acquired MTO-modified SC90 cathode displays desirable capacity retention and high-voltage stability. When paired with commercial graphite anodes, the pouch-type cells with the MTO-modified SC90 can deliver a high capacity of 175.2 mAh g-1 with 89.8% capacity retention after 500 cycles. This lattice-matching coating strategy demonstrate a highly effective pathway to maintain the structural and interfacial stability in electrode materials, which can be a pioneering breakthrough in commercialization of Ni-rich cathodes.

Self-assembled GeOX/Ti3C2TX Composites as Promising Anode Materials for Lithium Ion Batteries.

High-capacity germanium-based anode materials are alternative materials for outstanding electrochemical performance lithium-ion batteries (LIBs), but severe volume variation and pulverization problems during charging-discharging processes can seriously affect their electrochemical performance. In addressing this challenge, a simple strategy was used to prepare the self-assembled GeOX/Ti3C2TX composite in which the GeOX nanoparticles can grow directly on Ti3C2TX layers. Nanoscale GeOX uniformly renucleates on the surface and interlayers of Ti3C2TX, forming the stable multiphase structure, which guarantees its excellent electrochemical performance. Electrochemical evaluation has shown that the rate capability and reversibility of GeOX/Ti3C2TX are both greatly improved, which delivers a reversible discharge specific capacity of above 1400 mAh g-1 (at 100 mA g-1) and a reversible specific capacity of 900 mAh g-1 after 50 cycles while it still maintains a stable specific capacity of 725 mAh g-1 at 5000 mA g-1. Furthermore, the composite exhibits an exceptionally superior rate capability, making it a good electrochemical performance anode for LIBs.

Boosting Cell Performance of LiNi0.8 Co0.15 Al0.05 O2 via Surface Structure Design.

Although the high energy density and environmental benignancy of LiNi0.8 Co0.15 Al0.05 O2 (NCA) holds promise for use as cathode material in Li-ion batteries, present low rate capabilities, and fast capacity fade limit its broad commercial applications. Here, it is reported that surface modification of NCA cathode (R-3m) with 5 nm-thick nanopillar layers and Fm-3m structures significantly improves electrode structure, morphology, and electrochemical performance. The formation of nanopillar layers increases cycling and working voltage stability of NCA by shielding the host material from hydrofluoric acid and improves structural stability with the electrolyte. The modified NCA cathode exhibits an enhanced 89% capacity retention at a rate of 1 C over that of pristine NCA (75.2%) after 150 cycles and effectively suppresses working voltage fade (a drop of 0.025 V after 300 cycles) during repeated charge-discharge cycles. In addition, the diffusion barrier of Li ions in NCA crystals at 0.80 V is noticeably smaller than that of Li ions in pristine NCA (0.87 eV). These findings demonstrate that this unique surface structure design considerably enhances cycle and rate performance of NCA, which has potential applications in other Ni-rich layered cathode materials.

Ultrahigh-Rate Behavior Anode Materials of MoSe2 Nanosheets Anchored on Dual-Heteroatoms Functionalized Graphene for Sodium-Ion Batteries.

MoSe2 is a prospective anode material for Na-ion batteries because of its layered structure and high theoretical capacity, while the unsatisfied electrochemical performance limits its further development. Herein, we report MoSe2 nanosheets anchored on dual-heteroatoms functionalized graphene by a solvothermal method. The heteroatoms and carbon matrix coexist in the form of graphitic-N/pyridinic-N/pyrrolic-N and P-C/P═O bonds, which result in excellent electronic conductivity of the materials and provide abundant active sites for electrochemical process. Results indicated that organic intercalation increased the layer spacing of the materials to facilitate sodium-ion diffusion, and the in situ formed carbon networks improved the conductivity among the layers of the materials and alleviated volume expansion during the continued charge and discharge process. As an anode of Na-ion batteries, the nanosheets materials exhibited ultrahigh rate performance and deliver capacities of approximately 200 mAh g-1 at the current density of 10 A g-1. The ultrahigh-rate performance can be attributed to its unique nanosheets structure, the dual-heteroatoms functionalized graphene, and the considerable pseudocapacitive quality of the material.

Sugar sources as Co-substrates promoting the degradation of refractory dye: A comparative study.

Four sugar sources were used as co-substrates to promote the degradation of a selected refractory dye reactive black 5 (RB5) by the natural bacterial flora DDMZ1. The boosting performance of the four sugar sources on RB5 decolorization ranked as: fructose > sucrose > glucose > glucose + fructose. Kinetic results of these four co-metabolism systems agreed well with a first-order kinetic model. Four sugar sources stimulated the extracellular azoreductase secretion causing enhanced enzyme activity. An increased formation of low molecular weight intermediates was caused by the addition of sugar sources. The toxicity of RB5 degradation products was significantly reduced in the presence of sugar sources. The bacterial community structure differed remarkably as a result of sugar sources addition. For a fructose addition, a considerably enriched population of the functional species Burkholderia-Paraburkholderia and Klebsiella was noted. The results enlarge our knowledge of the microkinetic and microbiological mechanisms of co-metabolic degradation of refractory pollutants.

Smartphone-based colorimetric chiral recognition of ibuprofen using aptamers-capped gold nanoparticles.

Sensitive and fast detection of ibuprofen enantiomers is very critical for required routine monitoring and risk assessment of trace pollutants in water samples. Here a simple, rapid and highly sensitive android smartphone application for chiral recognition was developed. Aptamer-capped gold nanoparticles (AuNPs) was demonstrated as an efficient detection platform for (S)-(+)-ibuprofen (S-Ibu) and (R)-(-)-ibuprofen (R-Ibu). Detachment of an enantioselective aptamer from the AuNPs surface and binding with an enantiomer of Ibu lead to AuNPs aggregation, which allows a rapid enantiodiscrimination of Ibu by monitoring the absorbance changes of AuNPs solution in the UV-vis spectrum. Under optimal conditions, the limit of detection for S-Ibu and R-Ibu was 1.24 and 3.91 pg/mL, respectively. These probes showed good chiral recognition ability in mixed samples (i.e. S-Ibu + R-Ibu) and environmental samples. These advantages can be further developed by quantitative measurement with smartphone, which opens new opportunities for on-site detection of trace chiral pollutants in a simple and practical manner.

"Soggy-Sand" Chemistry for High-Voltage Aqueous Zinc-Ion Batteries.

The narrow electrochemical stability window, deleterious side reactions, and zinc dendrites prevent the use of aqueous zinc-ion batteries. Here, aqueous "soggy-sand" electrolytes (synergistic electrolyte-insulator dispersions) are developed for achieving high-voltage Zn-ion batteries. How these electrolytes bring a unique combination of benefits, synergizing the advantages of solid and liquid electrolytes is revealed. The oxide additions adsorb water molecules and trap anions, causing a network of space charge layers with increased Zn2+ transference number and reduced interfacial resistance. They beneficially modify the hydrogen bond network and solvation structures, thereby influencing the mechanical and electrochemical properties, and causing the Mn2+ in the solution to be oxidized. As a result, the best performing Al2 O3 -based "soggy-sand" electrolyte exhibits a long life of 2500 h in Zn||Zn cells. Furthermore, it increases the charging cut-off voltage for Zn/MnO2 cells to 2 V, achieving higher specific capacities. Even with amass loading of 10 mgMnO2 cm-2 , it yields a promising specific capacity of 189 mAh g-1 at 1 A g-1 after 500 cycles. The concept of "soggy-sand" chemistry provides a new approach to design powerful and universal electrolytes for aqueous batteries.

Electrochemical selective lithium extraction and regeneration of spent lithium iron phosphate.

In this paper, a green, efficient and low-cost process for the selective recovery of lithium from spent LiFePO4 by anodic electrolysis is proposed. The leaching rates of Li, Fe and P under different conditions were explored and the optimal conditions are obtained. In the optimal conditions, Li, Fe and P leaching rates were 96.31%, 0.06% and 0.62% respectively. The Li/Fe selectivity was over 99.9%. The product obtained is isostructural FePO4 and retains the original particle morphology. The FePO4 obtained can be synthesised into LiFePO4/C by direct regeneration process or impurity removal regeneration process. The material synthesized by the latter process has a better electrochemical performance, with a discharge specific capacity of 144.5 mAh/g at 1.0C and a capacity retention of 92.0% over 500cycles. The superior performance can be attributed to an impurity removal process that reduced agglomeration and improved particle morphology.

Modulating Grain Boundary Networks to Achieve Superior Chemomechanical Coupling Properties in Nickel-Rich Cathode Materials.

To forge ahead with the next generation of power batteries boasting superior energy density, nickel-rich layered oxides are regarded as some of the most promising cathode materials. However, challenges such as microcracks, which are attributed to the elevated nickel content of the materials, have posed impediments to their further development and application. Consequently, this article focuses on the understanding of the materials in the deep delithiation state, dissecting their degradation mechanisms through a dual lens of electrochemical and mechanical properties. The comprehensive analysis reveals that microcracks within the particles exhibit a degree of reversibility. However, with repeated Li+ de-/intercalation, these microcracks progressively propagate and permeate the entire particle, ultimately leading to particle fragmentation. Therefore, this study employs Dy2O3 as an inducer to facilitate the growth of primary crystal grains, reducing the internal porosity of the particles. This effectively enhances the conductivity and lithium-ion diffusion kinetics in deep lithium-ion deintercalation states of nickel-rich cathode materials. The modified material exhibits significant suppression of microcrack formation and growth during cycling, leading to notable improvements in its chemical-mechanical properties. These degradation mechanisms and modification strategies of Ni-rich cathodes offer valuable insights into the development of Ni-rich cathode materials tailored for electric vehicles.

Mg/Al Double-Pillared LiNiO2 as a Co-Free Ternary Cathode Material Ensuring Stable Cycling at 4.6 V.

Cobalt-free (Co-free) and nickel-rich (Ni-rich) cathode materials have attracted significant attention and undergone extensive studies due to their affordability and superior energy density. However, the commercialization of these Co-free materials is hindered by challenges such as cation disorder, irreversible phase changes, and inadequate high-voltage performance. To overcome these challenges, a Co-free ternary cathode material of Mg/Al double-pillared LiNiO2 (NMA) synthesized via a wet-coating and lithiation-sintering technique is proposed. Fundamental studies reveal that Mg and Al have the potential to form a distinctive double-pillar structure within the layered cathode, enhancing its structural stability. To be specific, the strategic placement of Mg and Al in Li and Ni layers, respectively, effectively reduces Li+/Ni2+ disorder and prevents irreversible phase transitions. Additionally, the inclusion of Mg and Al refines the primary grains and compacts the secondary grains in the cathode material, reducing stress from cyclic usage and preventing material cracking, thereby mitigating electrolyte erosion. As a result, NMA demonstrates exceptional electrochemical performance under a high charge cutoff voltage of 4.6 V. It maintains 70% of initial specific capacity after 500 cycles at 1 C and exhibits excellent rate performance, with a capacity of 162 mAh g-1 at 5 C and 149 mAh g-1 at 10 C. As a whole, the produced NMA achieves a high structural stability in cases of excessive delithiation, providing a groundbreaking solution for the development of cost-effective and high-energy-density cathode materials for lithium-ion batteries.

An aqueous electrolyte densified by perovskite SrTiO3 enabling high-voltage zinc-ion batteries.

The conventional weak acidic electrolyte for aqueous zinc-ion batteries breeds many challenges, such as undesirable side reactions, and inhomogeneous zinc dendrite growth, leading to low Coulombic efficiency, low specific capacity, and poor cycle stability. Here, an aqueous densified electrolyte, namely, a conventional aqueous electrolyte with addition of perovskite SrTiO3 powder, is developed to achieve high-performance aqueous zinc-ion batteries. The densified electrolyte demonstrates unique properties of reducing water molecule activity, improving Zn2+ transference number, and inducing homogeneous and preferential deposition of Zn (002). As a result, the densified electrolyte exhibits an ultra-long cycle stability over 1000 cycles in Zn/Ti half cells. In addition, the densified electrolyte enables Zn/MnO2 cells with a high specific capacity of 328.2 mAh g-1 at 1 A g-1 after 500 cycles under an extended voltage range. This work provides a simple strategy to induce dendrite-free deposition characteristics and high performance in high-voltage aqueous zinc-ion batteries.

Construction of Planar Gliding Restriction Buffer and Kinetic Self-Accelerator Stabilizing Single-Crystalline LiNi0.9Co0.05Mn0.05O2 Cathode.

The single-crystalline Ni-rich cathode has aroused much attention for extenuating the cycling and safety crises in comparison to the polycrystalline cathode. However, planar gliding and kinetic hindrance hinder its chemo-mechanical properties with cycling, which induce delamination cracking and damage the mechanical integrity in single crystals. Herein, a robust Li2.64(Sc0.9Ti0.1)2(PO4)3 (LSTP) ion/electron conductive network was constructed to decorate single-crystal LiNi0.9Co0.05Mn0.05O2 (SC90) particles. Via physicochemical characterizations and theoretical calculations, this LSTP coating that evenly grows on the SC90 particle with good lattice matching and strong bonding effectively restricts the anisotropic lattice collapse along the c-axis and the cation mixing activity of SC90, thus suppressing planar gliding and delamination cracking during repeated high-voltage lithiation/delithiation processes. Moreover, such a 3D LSTP network can also facilitate the lithium-ion transport and prevent the electrolyte's corrosion, lightening the kinetic hindrance and triggering the surface phase transformation. Combined with the Li metal anode, the LSTP-modified SC90 cell exhibits a desirable capacity retention of 90.5% at 5 C after 300 cycles and stabilizes the operation at 4.3/4.5 V. Our results provide surface modification engineering to mitigate planar gliding and kinetic hindrance of the single-crystalline ultra-high Ni-rich cathode, which inspires peers to design other layered cathode materials.

Enhanced mechanical strength of a highly de-lithiated single-crystal Ni-rich cathode to suppress irreversible planar gliding.

The mechanical properties of de-lithiated single-crystal Ni-rich cathodes are causing extensive concern. Here, we first show that the compression hardness of single crystal Ni-rich cathode particles decreases significantly at highly de-lithiated states by micro-compression testing. Thus, phase-boundary hardening was introduced to inhibit the planar gliding, resulting in excellent electrochemical performance.

Double-Layer Electrolyte Boosts Cycling Stability of All-Solid-State Li Metal Batteries.

All-solid-state lithium metal batteries (ASSLMBs), as a candidate for advanced energy storage devices, invite an abundance of interest due to the merits of high specific energy density and eminent safety. Nevertheless, issues of overwhelming lithium dendrite growth and poor interfacial contact still limit the practical application of ASSLMBs. Herein, we designed and fabricated a double-layer composite solid electrolyte (CSE), namely, PVDF-LiTFSI-Li1.3Al0.3Ti1.7(PO4)3/PVDF-LiTFSI-h-BN (denoted as PLLB), for ASSLMBs. The reduction-tolerant PVDF-LiTFSI-h-BN (denoted as PLB) layer of the CSE tightly contacts with the Li metal anode to avoid the reduction of LATP by the electrode and participates in the formation of a stable SEI film using Li3N. Meanwhile, the oxidation-resistance and ion-conductive PVDF-LiTFSI- LATP (denoted as PLA) layer facing the cathode can reduce the interfacial impedance by facilitating ionic migration. With the synergistic effect of PLA and PLB, the Li/Li symmetric cells with sandwich-type electrolytes (PLB/PLA/PLB) can operate for 1500 h with ultralong cycling stability at 0.1 mA cm-2. Additionally, the LiFePO4/Li cell with PLLB maintains satisfactory capacity retention of 88.2% after 250 cycles. This novel double-layer electrolyte offers an effective approach to achieving fully commercialized ASSLMBs.

Study of Synergistic Effects of Cu and Fe on P2-Type Na0.67MnO2 for High Performance Na-Ion Batteries.

P2-type Na0.67MnO2 with a stable structure and an open framework can provide numerous channels for fast Na+ de/intercalation, for which it is considered to be advantageous in application of the cathode material for Na-ion batteries. However, the complex phase transition occurring during cycling and the lattice distortion triggered by the Jahn-Teller effect severely restrict its development. Herein, the modified Na0.67MnO2 with Cu or Fe single-element doping as well as Cu and Fe double-element doping was synthesized by the sol-gel method, and the effects of doping on the crystal structure and electrochemical performances of Na0.67MnO2 were studied. It was demonstrated that the phase of the material did not change after the introduction of Cu and Fe elements, and the cycling stability and rate performance were greatly improved by Cu and Fe double-doping owing to their synergistic effect. The Na0.67Mn0.92Fe0.04Cu0.04O2 (NMFCO) cathode delivers discharge specific capacities of 110.5 mA h g-1 at 5 C and 91.8 mA h g-1 at 10 C and exhibits the high-capacity retention of 94.35% at 1 C and 90.68% at 5 C after 100 cycles. Overall, this study offers a guiding direction for accelerating the modification of P2-type Na0.67MnO2 as a cathode active material for high performance Na-ion batteries.

Recent Advances on Heterojunction-Type Anode Materials for Lithium-/Sodium-Ion Batteries.

Rechargeable batteries are key in the field of electrochemical energy storage, and the development of advanced electrode materials is essential to meet the increasing demand of electrochemical energy storage devices with higher density of energy and power. Anode materials are the key components of batteries. However, the anode materials still suffer from several challenges such as low rate capability and poor cycling stability, limiting the development of high-energy and high-power batteries. In recent years, heterojunctions have received increasing attention from researchers as an emerging material, because the constructed heterostructures can significantly improve the rate capability and cycling stability of the materials. Although many research progress has been made in this field, it still lacks review articles that summarize this field in detail. Herein, this review presents the recent research progress of heterojunction-type anode materials, focusing on the application of various types of heterojunctions in lithium/sodium-ion batteries. Finally, the heterojunctions introduced in this review are summarized, and their future development is anticipated.

Enhancing Cell Performance of Lithium-Rich Manganese-Based Materials via Tailoring Crystalline States of a Coating Layer.

Li-rich Mn-based-layered oxides are considered to be the most felicitous cathode material candidates for commercial application of lithium-ion batteries on account of high energy density. Nevertheless, defects containing an unsatisfactory initial Coulombic efficiency and rapid voltage decay seriously impede their practical utilization. Herein, a coating layer with three distinct crystalline states are employed as a coating layer to modify Li[Li0.2Mn0.54Ni0.13Co0.13]O2, respectively, and the effects of coating layers with distinct crystalline states on the crystal structure, diffusion kinetics, and cell performance of host materials are further explored. A coating layer with high crystallinity enables mitigatory voltage decay and better cyclic stability of materials, while a coating layer with planar defects facilitates Li+ transfer and enhances the rate performance of materials. Consequently, optimizing the crystalline state of coating substances is critical for preferable surface modification.

Deciphering the mechanism of carbon sources inhibiting recolorization in the removal of refractory dye: Based on an untargeted LC-MS metabolomics approach.

In this study, the biological decolorization of reactive black 5 (RB5) by Klebsiella sp. KL-1 in yeast extract (YE) medium was captured the recolorization after exposure to O2, which induced a 15.82% reduction in decolorization efficiency. Similar result was also observed in YE + lactose medium, but not in YE + glucose/xylose media (groups YE + Glu/Xyl). Through biodegradation studies, several degradation intermediates without quinoid structure were produced in groups YE + Glu/Xyl and differential degradation pathways were deduced in diverse groups. Metabolomics analysis revealed significant variations in up-/down-regulated metabolites using RB5 and different carbon sources. Moreover, the underlying mechanism of recolorization inhibition was proposed. Elevated reducing power associated with variable metabolites (2-hydroxyhexadecanoic acid, 9(R)-HODE cholesteryl ester, linoleamide, oleamide) rendered additional reductive cleavage of C-N bond on naphthalene ring. This study provided a new orientation to inhibit recolorization and deepened the understanding of the molecular mechanism of carbon sources inhibiting recolorization in the removal of refractory dyes.

In Situ-Formed Hollow Cobalt Sulfide Wrapped by Reduced Graphene Oxide as an Anode for High-Performance Lithium-Ion Batteries.

Transition-metal sulfides have been considered as promising anode materials for lithium-ion batteries (LIBs) due to their high theoretical specific capacity and superior electrochemical performance. However, the large volume change during the discharge/charge process causes structural pulverization, resulting in rapid capacity decline and the loss of active materials. Herein, we report Co1-xS hollow spheres formed by in situ growth on reduced graphene oxide layers. When evaluated as an anode material for LIBs, it delivers a specific capacity of 969.8 mAh·g-1 with a high Coulombic efficiency of 96.49% after 90 cycles. Furthermore, a high reversible capacity of 527.2 mAh·g-1 after the 107th cycle at a current density of 2.5 A g-1 is still achieved. The results illustrate that in situ growth on the graphene layers can enhance conductivity and restrain volume expansion of cobalt sulfide compared with ex situ growth.

Optimal Quantity of Nano-Silicon for Electrospun Silicon/Carbon Fibers as High Capacity Anodes.

In this study, silicon/carbon composite nanofibers (Si@CNFs) were prepared as electrode materials for lithium-ion batteries via a simple electrospinning method and then subjected to heat treatment. The morphology and structure of these materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the structure provides good electrical conductivity and affords sufficient space to accommodate volume expansion during charging/discharging. Furtherly, electrochemical performance tests show that the optimized Si@CNFs have an initial reversible capacity of 1,820 mAh g-1 at a current density of 400 mA g-1 and capacity retention of 80.7% after 100 cycles at a current density of 800 mA g-1. Interestingly, the optimized Si@CNFs have a superior capacity of 1,000 mAh g-1 (400 mA g-1) than others, which is attributed to the carbon substrate nanofiber being able to accommodate the volume expansion of Si. The SEI resistance generated by the Si@CNFs samples is smaller than that of the Si nanoparticles, which confirms that SEI film generated from the Si@CNFs is much thinner than that from the Si nanoparticles. In addition, the connected carbon substrate nanofiber can form a fiber network to enhance the electronic conductivity.