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A novel polymer electrolyte with high stability and high performance is prepared by in situ polymerization for lithium metal batteries.

Reactive oxygen species (ROS) play an important role in living activities as signaling molecules that regulate the living activities of organisms. There are many types of ROS, mainly including hydrogen peroxide (H

Nitrogen-doped nanocarbon materials (NCMs) have been developed as promising metal-free oxygen reduction reaction (ORR) electrocatalysts. However, insufficient attention on the balance of N-doping engineering and carbon chemistry significantly suppressed the revelation of the real active configurations as well as the ORR mechanism for NCMs. Herein, 1,4-phenylenediurea (BDU) with multifunctional blocks was designed for the synthesis of NCMs, realizing synchronous manipulation of N-doping engineering and carbon chemistry. The good balance between N-doping engineering (especially graphitic edge N configurations) and carbon chemistry (including the specific surface area, porosity distribution, and graphitization degree) at a pyrolysis temperature of 1000 °C resulted in the best ORR performance for obtaining N-doped carbon nanorod (NCR) materials. A general descriptor χ was then proposed for evaluating the balance states between N-doping engineering and carbon chemistry. The prediction of the ORR performance of NCMs from their physical properties as well as searching for the optimal active configuration from the relationships between ORR performance and different configurations can be realized from such a practical descriptor, which can also be extended to other nanocarbon-based metal-free electrocatalytic reactions for deeply understanding their electrocatalytic mechanisms.

In recent years, with the rapid development of electric vehicles, the ever-fluctuating cobalt price has become a decisive constraint on the supply chain of the lithium-ion (Li-ion) battery industry. To address these challenges, a new and unreported cobalt-free (Co-free) material with a general formula of LiNi0.8Fe0.1Mn0.1O2 (NFM) is introduced. This Co-free material is synthesized via the coprecipitation method and examined by using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) to investigate the morphological, crystal-structure, and electrochemical properties. The NFM cathode can deliver a specific capacity of 202.6 mA h g-1 (0.1C, 3.0-4.5 V), a specific energy capacity of 798.8 W h kg-1 in material level (0.1C, 3.0-4.5 V), a reasonable rate capability, and a stable cycling performance (81.1% discharge capacity retention after 150 cycles at 10C, 3.0-4.3 V). Although the research on this subject is still in its early stage, the capability of this novel cathode material as a practical candidate for applications in next-generation Co-free lithium-ion batteries (LIBs) is highlighted in this study.

Elevated HClO gets involved in the pathogenesis of Parkinson's disease (PD). Herein, a novel fluorescent probe NUU-1 was designed and synthesized. Distinct from the general strategies, NUU-1 features two distinct HClO reactive sites, a HClO-specific reaction site and a HClO-nonspecific reactive site, which in turn endows NUU-1 with the "0 + 1 > 1" amplification effect, that thus dramatically promotes the selectivity. NUU-1 displayed a fast response rate (within 15 s), remarkable fluorescence enhancement (about 538-fold), and excellent sensitivity (LOD = 25.8 nM) in response to HClO while the remaining fluorescence silence toward other common ROS (H2O2, •OH, ONOO-, O2•-, and 1O2) even at high concentrations (up to 0.5 mM). NUU-1 allows for the imaging of both exogenous and endogenous HClO in living dopaminergic cells (SH-SY5Y). Moreover, by employing NUU-1 as the probe, the image of HClO in C. elegans and zebrafish was successfully achieved. Significantly, in the first trial, NUU-1 was successfully utilized for the brain basal HClO imaging in PD mice models and distinguished PD brain tissues from normal control, thereby holding great potential for in-depth biological applications.

Frosting has always been a crucial problem for air source heat pumps (ASHPs) operated in heating mode. Quantitative evaluation of frosting is of vital importance to the development of technologies against frosting. Although frosting maps have been developed in many studies, they are specific for unique systems. To evaluate the frosting performance of arbitrary system, a semi-experimental method, to depict frosting evaluation plot, was proposed in the present study. In the frosting evaluation plot, frosting region was clarified, and the frosting driving forces with the effect air temperature and relative humidity (RH) were evaluated, through theoretical calculation of Gibbs free energy change. After that, experiments were conducted to verify the frosting evaluation plot, and the results demonstrated the present method was feasible. In some experimental cases, the inlet segment of the heat exchanger escaped from frosting but the outlet segment frosted. As implementation of the semi-experimental method, the methodology was utilized to clarify the air temperature and RH ranges causing uneven frosting. In addition, the frosting evaluation plot with impact of air velocity was drawn. The results suggested that, increased air velocity restrained frosting, and reduced the chance of uneven frosting.

A deep eutectic solvent (DES) is a promising electrolyte choice for lithium metal batteries. However, the DES liquid electrolyte causes safety concerns and side reactions with the lithium anode. Therefore, it is necessary to solidify the DES-based electrolyte and enhance its electrochemical stability. Herein, we present a novel DES-based rapid self-healing gel electrolyte, which is able to self-smooth its surface cracks in only 30 min. The electrolyte exhibits noncombustibility (SET = 4 s g

Platinum group metal (PGM)-free catalysts are highly desirable for oxygen reduction reaction (ORR) for clean energy. To prevent possible Fenton reaction, a catalyst containing manganese-nitrogen-carbon coordination structure (Mn-N–C) supported on monolayer graphene (Mn-N–C/G) is synthesized through a self-developed tailoring, self-assembling, and reconstructing vapor phase deposition (TSRVD) process using manganese phthalocyanine (MnPc) as the precursor. The novel catalyst Mn-N–C/G with high-density and well-organized distribution of manganese ion center coordinated with five nitrogen (Mn-N5) active sites, efficient electron-conductivity from the carbon six-member ring, and ideal structural stability shows an onset potential of 0.99 V vs. RHE and current density of 1.3 mA cm−2 at potential 0.88 V vs. RHE compared with commercial Pt/C (0.96 V vs. RHE and 1.1 mA cm−2, respectively). Based on the analyses of SEM, HRTEM, XRD, SAED, Raman, and XPS on catalyst Mn-N–C/G, a reasonable formation model of catalyst Mn-N–C/G is proposed.

A universal anode material of 1D core-shell MoO2@MoS2/nitrogen-doped carbon (MoO2@MoS2/NC) nanorods has been elaborately synthesized via a facile fabrication route for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), in which MoO2 core not only acts as a conductive backbone for efficient electron transport, but creates structural disorders in MoS2 nanosheets to prevent aggregation and expose more active sites for alkali-ions. Meanwhile, the MoO2 core is tightly encapsulated by the parallelly aligned MoS2 nanosheets to constrain the size of crystals, which greatly shortens the ionic diffusion path and accelerates diffusion rate, thus ensuring fast reaction kinetics. Additionally, the resilient and conductive N-doped carbon matrix in the hybrid could maintain the structural integrity and enhance the electrical conductivity of the electrodes, improving the rate capability and life span. The flexible 1D nanorods could contract freely during the charge/discharge process, further assuring the structural stability of the electrodes. Benefiting from the above-mentioned advantages, the MoO2@MoS2/NC electrodes still remains a specific capacity of 583.5 mA h g−1 after 1500 cycles at a high current density up to 10 A g−1 in LIBs, and a capacity of 419.8 mA h g−1 is steadily kept over 800 cycles at 2 A g−1 in SIBs.

LiNixCoyMn1-x-yO2 (x ≥ 0.5) layered oxide materials are generally considered as one of the most prospective candidates for lithium-ion battery (LIBs) cathodes due to their high specific capacity and working voltage. However, surface impurity species substantially degrade the electrochemical performance of LIBs. Herein, surface reconstruction from layered structure to disordered layer and rock-salt coherent region together with a uniform Li2CO3-dominant coating layer is first in situ constructed on the single-crystal LiNi0.5Co0.2Mn0.3O2 (NCM) material by a simple water treatment procedure. The unique surface structure is elucidated by Ar-sputtering-assisted X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (spherical aberration-corrected-scanning transmission electron microscopy (STEM), high-resolution transmission electron microscopy (HRTEM), and TEM). Meanwhile, neutron powder diffraction (NPD) indicates that the antisite defect concentration is mitigated in the treated materials. The modified samples display superior cycle stability with a capacity retention of up to 87.5% at 1C after 300 cycles, a high rate capacity of 151 mAh g-1 at 5C, an elevated temperature (45 °C) cycling property with 80% capacity retention (4.5 V), and improved full-cell performance with 91% after 250 cycles at 1C. Importantly, postmortem examination on the cycled cathodes by time-of-flight secondary-ion mass spectroscopy (TOF-SIMS), XPS, TEM, and X-ray diffractometer (XRD) pattern further demonstrate that these results are mainly attributed to the thin cathode electrolyte interface (CEI) film and low solubility of transition-metal ions. Therefore, this expedition provides an opportunity to construct an effective armor for the interface compatibility and stability of LIBs.

Li1.5Al0.5Ge1.5(PO4)3 (LAGP)-PEO composite electrolytes are unstable in LiMn2O4. In addition, the discharge platform potential (2.8 and 4.0 V) difference of LiMn2O4 is relatively large, whereas the discharge platform potential (3.5 V) of LiFePO4 is between 2.8 and 4.0 V. Thus, LiMn2O4 and LiFePO4 can be compounded together to reduce the material platform voltage difference and obtain the advantages of both materials at the same time. Here, LiMn2O4/LiFePO4 composite cathodes were applied in solid-state batteries. LAGP-PEO(LiTFSI) was used as the electrolyte. The Li/composite cathode battery using composite electrolytes has a reversible capacity of 192.8 mAh g-1 at 50 °C and 0.1 C. It possesses favorable rate performance and exhibits very good cycling stability. In addition, the composite electrolytes can prevent the further occurrence of the Jahn-Teller effect. Meanwhile, the charge-transfer resistance slightly decreases in 10 cycles. The excellent capacity retention of the battery is connected with the excellent electrochemical stability and the well-interfaced contacts of the composite electrolytes with electrodes.

A polymer electrolyte with high elasticity and high performance is prepared by IN SITU polymerization. The polymer electrolyte is amorphous and has a high ionic conductivity of 7.9 × 10-4 S cm-1 and good elasticity. The discharge capacity of Li/LiFePO4 in the 100th cycle is 133.90 mA h g-1 (0.5C, 25 °C).

Fe–N–C single-atom catalysts usually exhibit poor ORR activity due to their unsatisfactory O2 adsorption and activation. Here, a new design idea and tailored self-assembly synthesis method are reported to improve their ORR performance. DFT calculations indicate that the ORR electrocatalytic activity of Fe–N–C single-atom catalysts with an axial structure is superior to that of Fe–N–C single-atom catalysts with a Fe–N4 active site. In order to experimentally demonstrate the difference, Fe–N–C single-atom catalysts with a Fe–N5 active site were successfully synthesized on the surface of monolayer graphene. XANES, SEM, HRTEM, XRD, Raman and XPS analyses indicate that the synthesized Fe–N–C catalyst possessed nanofibre morphology and a curved layer-like crystal structure. For comparison, FePc powder was used as the FePc(Fe–N4) catalyst as its molecular structure involves a Fe–N4 active site embedded in carbon six-membered rings. The current density of the synthesized Fe–N5/C@G catalyst at a potential of 0.88 V vs. RHE is 1.65 mA cm−2, which is much higher than that of the FePc(Fe–N4) catalyst (1.04 mA cm−2) and even higher than that of commercial Pt/C catalyst (1.54 mA cm−2). The results are very well consistent with the DFT calculations, verifying the dependability and accuracy of DFT calculations. This work reports a new synthetic idea to obtain better performance and proposes a formation mechanism to explain the process of the synthesis method.

High cost, complex synthesis routes and low yield are pressing challenges hindering the practical application of organic battery materials. Herein, copper(II) phthalocyanine (CuPc), one of the most frequently used blue pigments, is directly used as a cathode material in lithium ion batteries. CuPc has a well-defined discharge voltage plateau that is higher than 3.6 V. The discharge capacity of CuPc at 1C of 93.1 mA h g−1 is close to the theoretical discharge capacity. Even at a high rate of 50C, the material remains close to its discharge capacity of 1C, without discernible polarization of the voltage. In addition, CuPc maintains 67% of its initial capacity after 1000 cycles at 20C with nearly 100% coulombic efficiency. Additionally, at high charging voltages, the benzene rings between the CuPc molecules undergo self-polymerization reactions that are catalysed by the copper(II) ions in CuPc.

A general and simple strategy is realized for the first time for the preparation of metal sulfide (Mx Sy ) nanoparticles immobilized into N/S co-doped carbon (NSC) through a one-step pyrolysis method. The organic ligand 1,5-naphthalenedisulfonic acid in the metal-organic framework (MOF) precursor is used as a sulfur source, and metal ions are sulfurized in situ to form Mx Sy nanoparticles, resulting in the formation of Mx Sy /NSC (M=Fe, Co, Cu, Ni, Mn, Zn) composites. Benefiting from the Mx Sy nanoparticles and conductive carbon, a synergistic effect of the composite is achieved. For instance, the composite of Fe7 S8 /NSC as an anode displays excellent long-term cycling stability in lithium/sodium ion batteries. At 5 A g-1 , large capacities of 645 mA h g-1 and 426.6 mA h g-1 can be retained after 1500 cycles for the lithium-ion battery and after 1000 cycles for the sodium-ion battery, respectively.

Lithium metal anode (LMA) is the ultimate “Holy Grail” electrode for next generation high-energy-density batteries. Nevertheless, its instinct high reactivity is a formidable challenge and has intensified side reactions, destabilized the electrode/electrolyte interface and restricted the operating conditions strictly, thus hampering its practical application. Here, we “make up” the Li metal (M-Li) by constructing vaseline-coated layer by a simple dip-coating or casting method. With the chemically stable and hydrophobic vaseline protective layer, the stability of Li towards humid and corrosive atmosphere has been greatly improved. The M-Li guaranteed stable and prolonged cycling life after the anode suffering from corrosion in moist air (relative humidity ~65%) or corrosive electrolyte (with 10,000 ppm H2O or S) both in symmetric cells and LiFePO4 full cells. This work illustrates a convenient, economic, and industrial applicable method for stable LMA.

Hierarchical architecture of porous anatase TiO2 microspheres are obtained by a universal solvothermal reaction, which can improve the cycling stability and ionic/electronic transport properties in...

Inorganic solid-state electrolyte (SSE) has offered a promising option for the safe rechargeable Li metal batteries. However, the solid-solid interfacial incompatibility greatly hampers the practical use. The interface becomes even worse during repeated Li plating/stripping, especially under high current density and long cycling operation. To promise an intimate contact and uniform Li deposition during cycling, we herein demonstrate a stress self-adapted Li/Garnet interface by integrating Li foil with a hyperelastic substrate. Consecutive and conformal physical contact was ensured at Li/Garnet interface during Li plating/stripping, therefore dissipating the localized stress, suppressing Li dendrite formation, and preventing Garnet cracks. Record long cycling life over 5000 cycles was achieved with the ultrasmall hysteresis of 55 mV at high current density of 0.2 mA cm-2. Our strategy provides a new way to stabilize Li/Garnet interface from the perspective of anode mechanical regulation and paves the way for the next generation solid-state Li metal batteries.

As two important reactive oxygen species, hydrogen peroxide (H2O2) and hypochlorous acid (HClO) play vital roles in many physiological and pathological processes. However, the relationship between these two species is seldom investigated, in part, because of the lack of robust molecular tools that can simultaneously visualize HClO and H2O2 in biosystems. In this work, we present a design strategy to construct a single fluorescent probe that can detect H2O2 and HClO by simultaneously monitoring two distinct detection channels. In the design, one phenothiazine-based coumarin serves as a chromophore and sensor for HClO, while a second coumarin precursor containing a boronate ester acts as a sensor for H2O2. After a head-to-head screening of three candidates differing in their coumarin precursor moieties, probe CSU1 was found to have the optimal characteristics. As shown experimentally, it is able to detect them selectively and sensitively to generate distinct fluorescence signals and patterns in living cells. Furthermore, the endogenous generation of HClO from H2O2 and Cl- catalyzed by myeloperoxidase enzyme in living cells can be clearly monitored by the probe. These studies demonstrate the potential of the probe as a powerful tool to investigate the interplay of HClO and H2O2 in oxidative stress.

In this work, we based on an iminocoumarin borate complex to design and synthesize a red-emitting fluorescent probe, THQ-BF2-O-NBD, to discriminatively detect Cys/Hcy and GSH with a large Stokes shift (100 nm). This probe responded to GSH to display red fluorescence with λmax = 630 nm. In contrast, two well-separated emission bands with λmax = 565 and 630 nm were observed in the solution of THQ-BF2-O-NBD with Cys/Hcy. The probe was capable to distinguish Cys/Hcy from GSH in real biological systems.

Promoting the reversible structural transformation and carrier migration dynamics simultaneously in a multiple ion-involved process is vital for sulfide electrode materials. Herein, TiS2 with a sulfide cluster vacancy (CV–TiS2−x) has been calculated and prepared to explore a novel strategy to improve the electrochemistry reversibility of sulfide electrodes. It is found that the cluster vacancy can serve as an effective control factor for the improvement of the Fermi level, and enhances the electrochemical stability of CV–TiS2−x in the liquid organic electrolyte system. Moreover, owing to the plentiful positively charged S-vacancies, the CV–TiS2−x samples exhibit an extended interplanar spacing and retain their structural integrity during the lithium ion insertion process. The integrated HRTEM, in situ XRD, XPS analysis and electrochemical study reveal that the cluster vacancy is not only responsible for an increase in reversible performance, but also boosting the anionic redox reaction of (S2)2− species. Therefore, the CV–TiS2−x electrode delivers a reversible capacity of 650 mA h g−1 for 300 cycles at a current density of 1C (220 mA g−1). Our study provides a novel strategy of introducing sulfur cluster vacancies to improve the electrochemical activity of TiS2, which can be applied to other sulfide electrodes.

A new layered structural Ni-MOF nanosheet has been successfully synthesized and used for the first time as an electrode for a supercapacitor and a flexible all-solid-state asymmetric supercapacitor, exhibiting capacitances of 1518.8 F g−1 at 1 A g−1 and 244 mF cm−2 at 0.5 mA cm−2, respectively.

In recent years, with the rapid development of electric vehicles, the ever-fluctuating cobalt price has become a decisive constraint on the supply chain of the lithium-ion (Li-ion) battery industry. To address these challenges, a new and unreported cobalt-free (Co-free) material with a general formula of LiNi

With the increasing diversification of portable electronics and large-scale energy storage systems, conventional lithium-ion batteries (LIBs) with graphite anodes are now approaching their theoretical limits. Lithium metal, as the "Holy Grail" electrode for next-generation rechargeable batteries, is being revisited to meet the booming demand for high energy density electrodes due to its ultrahigh theoretical specific capacity and negative redox potential. Nevertheless, typical issues like notorious dendrite growth still hamper the bulk application of Li metal anodes. Dendrite growth renders increased surface area of the lithium metal, causing persistent depletion of the electrolyte and active materials, facilitating catastrophic failure of the battery, and even inducing fatal safety hazards. The consequences become more serious during operation at high current densities and over long cycling life. Therefore, it is urgent to suppress and even eliminate dendrite formation during the Li plating/stripping process. This Account highlights several innovative strategies for dendrite suppression, dendrite regulation, and dendrite elimination from the perspective of interface energy and bulk stresses. First, we review the fundamental mechanism of dendrite formation and growth in Li metal anodes. We show that the dendrite morphology could be substantially ameliorated, in theory, by homogenizing the electric field distribution, lowering the Li ion concentration gradient, and facilitating mechanical blocking. Next, we address the problem of dendrite suppression by applying two-dimensional (2D) materials to Li metal systems and preventing dendrite penetration through stress release and mechanical blocking. Graphene with a high specific area and vermiculite sheets (VSs) with a large physical rigidity were demonstrated to be efficacious in reinforcing Li anodes and polymer electrolytes separately. However, Li dendrite growth is a continuous process and remains inevitable with increasing current density and cycling life. Instead of suppressing dendrite growth, we focus on how to regulate homogeneous Li dendrite formation and growth. Dendrite regulation means to allow dendrite growth but take steps to transform it into Li with a smooth morphology. We introduce two main strategies to regulate Li growth: (i) guiding Li nucleation and (ii) controlling the Li growth pathways and directions. These processes greatly rely on the interface energy between the substrate and Li atoms. Elimination of the dendrites, which is the most formidable challenge for dendrite control, can also be achieved by dynamically engineering the force, such as deflecting the electric field by Lorentz force in a magnetic field, enhancing the integrated yield stress by the design of bulk nanostructured materials, and reducing the lateral Li diffusion barrier by a biomimetic co-deposition process. Solutions to the challenges of dendrite control in Li metal anodes can provide safe next-generation rechargeable lithium metal batteries that have a long cycling life. We also hope that our strategies presented in this Account can offer promise for other metal batteries.

The Li/CFx primary battery with the highest energy density has been widely applied in many fields. However, the Li/CFx battery has been suffering from some problems for large-scale applications, su...

The core-shell hierarchical mesoporous titanium dioxides with situ nitrogen dopen carbon and the stable architecture are synthesized by a feasible route, basing on the sol-gel, freeze-drying and calcination process. Nitrogen doped carbon is synergistically compounded with nano-TiO2 to fabricate the hybrid composite (C-N@MP-TiO2), which has high surface area of 318 m2 g−1 and large average pore size of 6.8 nm. This corresponding anode consisted of the hybrid composite exhibits superior specific capacity, rate capability, and long cycling stability. Also, the initial discharge capacity is up to 360 mAh g−1 at the current density of 0.1 A g−1 with the good capacity retention of 97% after 350 circles. The excellent rate performance presents the capacity of 173.6 mAh g−1 at the current density of 5 A g−1. Moreover, the large current reversible capacity (20 A g−1) can reach 172.2 mAh g−1 with long-term cycling stability over 500 cycles. Therefore, the superior electrochemical performances are attributed to the stable core-shell mesoporous structure and in-situ nitrogen doped carbon, which is not only improve the electron transport and lithium ion diffusion, but also facilitate the immersion of electrolyte.

Owing to the expanding function of Li-ion transmission channels, it is important to explore the doping effects of different compounds into sulfide solid electrolytes to improve their electrochemical performances. However, it is hard to characterize the doping behaviors within sulfide solid electrolytes with low crystallinity and poor stability just by conventional crystallography analytical methods. In this work, the dielectric spectrum testing combined with other analytical methods, such as 7Li solid-state nuclear magnetic resonance, X-ray photoelectron spectroscopy, and the electrochemical method, have been applied to investigate the dual-doping behaviors of WS2 and LiBr within Li7P3S11 glass-ceramic electrolytes. This research method can not only evaluate the internal acting effect between the skeleton of sulfide solid electrolytes and the migrating kinetics of Li ions but also explore the capacitance at the interfaces of LiCoO2/sulfide solid electrolytes. The experimental results show that the number of Li ions with fast transport velocity within Li2S-P2S5-based solid electrolytes has been increased. Meanwhile, the interfacial capacitances between Li2S-P2S5-based solid electrolytes and the LiCoO2 cathode have decreased after dual-doping of WS2 and LiBr, indicating a synergetic effect for the doped Li7P3S11 glass-ceramic electrolytes in terms of the ionic conductivities and interfacial compatibilities. This work may provide a novel analytical approach to explore both the diffusion kinetics and interfacial behaviors for the solid electrolytes of lithium batteries.