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Recently, zero-dimensional (0D) metal halides have made remarkable achievements in the field of optoelectronics due to their diverse structures and optical performances. Here, we report 0D (TBA)2Cu2I4 (TBA+ = tetrabutylammonium cation) single crystals (SCs), which shows a dual-emission band at 473 and 699 nm and a bright cool-white emission with a high photoluminescence quantum yield (PLQY) of 72.5% at room temperature (RT). The temperature-dependent emission spectra and Raman spectra show that a dual self-trapped exciton (STE) is present in this compound, and the external thermal energy can effectively regulate the population of STEs in the two emitting states, and thus the emission color can be changed from blue at a low temperature (78 K) to a cool-white emission at RT. More specifically, (TBA)2Cu2I4 SCs possess high anti-water stability, and can maintain highly efficient emission even if immersed in water for 24 hours. Also noteworthily, the high thermal stability, air stability and photostability of this component have also been proved.

Low-dimensional organic–inorganic hybrid metal halides have drawn intense attention due to their flexible structures and outstanding optical properties. However, the toxicity of lead halides hinders their future application in optoelectronic devices. Herein, we report a zero-dimensional (0D) lead-free compound of (TPA)2SbCl5 (TTA+ = tetrapropylammonium cation) single crystals (SCs), which crystallizes in a triclinic system with P symmetry. Interestingly, (TPA)2SbCl5 exhibits a single broad orange emission band at 610 nm under low-energy excitation (e.g., 375 nm) with a high photoluminescence quantum yield (PLQY) of 95.3%, while it shows a dual-band emission profile with an additional narrow emission band at 466 nm at high-energy excitation (e.g., 300 nm), which is formed by the transformation of the doublet of spin–orbit interactions into two individual STEs. The Raman spectra supplied clear evidence for the self-trapped exciton (STE) with clear multiphonon modes in (TPA)2SbCl5, which reflects its strong nonlinear electron–phonon coupling. The emission mechanism for the temperature-dependent dual emission can be attributed to the radiative transitions of singlet STEs and triplet STEs in [SbCl5]2− clusters. Moreover, a white-light-emitting diode (WLED) was also fabricated by mixing (TPA)2SbCl5 with green (Ba2SiO4:Eu2+) and blue (BaMgAl10O17:Eu2+) phosphors, which exhibited CIE coordinates of (3.48, 3.50), a correlated color temperature (CCT) of 4900 K, and a color rendering index (CRI) of 93.2. Our achievements illustrate that the lead-free compound of (TPA)2SbCl5 has great potential in solid-state lighting.

Spinel LiNi0.5Mn1.5O4 (LNMO) is one of the most promising cathode materials for high-energy density lithium batteries owing to its high reversible capacity and high operating voltage. However, LNMO-based lithium batteries have poor cycling performance due to the decomposition of liquid electrolytes and dissolution of transition metal (e.g. Mn and Ni) ions at high operating voltages. Herein, poly(methyl vinyl ether-alt-lithium maleic acid) (P(MVE-LMA)) is presented as an excellent aqueous binder for the first time to tackle the abovementioned issues, in which the lithium carboxylic motifs of P(MVE-LMA) deliver superior adhesion and cohesion capabilities and interact with transition metal cations to inhibit their dissolution from cathodes, whereas its ether motifs can adsorb on the carbon particle surface to render excellent distribution of carbon black. As a result, a 5 V-class LNMO/Li battery fabricated employing the P(MVE-LMA) binder exhibited better electrochemical performance (e.g., cycling life, cell impedance and rate capability) when compared with the battery with the traditional polyvinylidene fluoride (PVDF) binder. A more thorough investigation clearly elucidated that the enhanced battery performance of the P(MVE-LMA) binder could be attributed to the generation of a favorable cathode electrolyte interphase (CEI) layer, in turn favorably suppressing the oxidative decomposition of electrolytes and stabilizing the lattice structure of LNMO upon cycling.

In this article, we demonstrated for the first time an ultra-strong bacterial cellulose supported poly(methyl vinyl ether-alt-maleic anhydride) as a multifunctional polymer electrolyte for a 4.45 V-class LiCoO2 lithium metal battery. Such a polymer electrolyte based LiCoO2 lithium metal battery delivered significant capacity retention (85% retention after 700 cycles) at 60 °C. A more thorough investigation elucidated that it played multiple roles in enhancing the electro-oxidative resistance and reversible lithium plating/stripping of a LiCoO2 lithium metal cell. These extraordinary features open up a new avenue for the fabrication of advanced polymer electrolytes for high-voltage lithium metal cells.

Solid electrolyte is regarded as a perfect way to enhance safety issues and boost energy density of lithium batteries. Herein, we developed a type of free-standing poly(propylene carbonate)/Li6.75La3Zr1.75Ta0.25O12 composite solid electrolyte for ambient temperature and flexible solid-state lithium batteries. The composite solid electrolyte exhibited excellent comprehensive performance in terms of high ionic conductivity (5.2 × 10−4 S cm−1) at 20 °C, a wide electrochemical window (4.6 V), high ionic transference number (0.75) and satisfactory mechanical strength (6.8 MPa). When evaluated as solid electrolyte for an ambient-temperature solid lithium battery, such a composite electrolyte delivered excellent rate capability (5C) at 20 °C. This superior performance can be comparable to a liquid electrolyte-soaked PP separator-based lithium battery at room temperature. To our knowledge, this is the best rate capability of a solid composite electrolyte for a solid lithium battery at ambient temperature. Moreover, such a composite electrolyte-based flexible LiFePO4/Li4Ti5O12 lithium ion battery delivered excellent rate capability and superior cycling stability. All these fascinating features make poly(propylene carbonate)/Li6.75La3Zr1.75Ta0.25O12 a very promising all-solid-state electrolyte for flexible solid lithium batteries. Our study makes a big step into addressing the challenges of ambient-temperature solid lithium batteries.

Two-electron transfer chemistry based on earth-abundant Mg and S offers great possibilities of delivering higher energy density than current Li-ion technology. The development of non-nucleophilic electrolytes that reversibly and efficiently plate and strip Mg is believed to be a major obstacle to the implementation of this divalent battery technology. In this study, we present a new type of organic magnesium borate-based electrolyte that primarily comprises tetrakis(hexafluoroisopropyl)borate anions [B(HFP)4]− and solvated cations [Mg4Cl6(DME)6]2+, which was synthesized via a facile in situ reaction of tris(hexafluoroisopropyl)borate [B(HFP)3], MgCl2 and Mg powder in 1,2-dimethoxyethane (DME). Rigorous analyses including NMR, mass spectroscopy and single-crystal XRD were conducted to identify the equilibrium species in the abovementioned solution. The as-prepared Mg-ion electrolyte exhibited unprecedented Mg plating/stripping performance, such as high anodic stability up to 3.3 V (vs. Mg/Mg2+), high ionic conductivity of 5.58 mS cm−1, a low overpotential of 0.11 V for plating processes and Coulombic efficiencies greater than 98%. By virtue of the non-nucleophilic nature of this electrolyte, a fully reversible Mg/S battery was constructed that displayed an extremely low overpotential of 0.3 V and a high discharge capacity of up to 1247 mA h g−1 and yielded a specific energy of approximately 1200 W h kg−1 (10 times higher that of the Chevrel benchmark) based on the weight of active sulfur. More significantly, commonly used sulfur-carbon nanotube (S-CNTs) cathodes with S contents of 80 wt% and S loadings of 1.5 mg cm−2 were demonstrated to withstand more than 100 cycles without obvious capacity decay and to enable fast conversion processes, which achieved a charging current rate of up to 500 mA g−1. Our findings convincingly validate the pivotal role of the newly designed non-nucleophilic Mg-ion electrolyte for practical Mg/S battery chemistry.

In the present work, a simple and sensitive flow injection chemiluminescent competitive immunoassay was developed for the determination of mercury(II) ion (Hg(2+)) based on carboxylic resin beads, a novel specific monoclonal antibody (McAb) and HRP enzyme-amplification. Resin beads with carboxyl groups were creatively employed as supports for immobilizing more coating antigen through acylamide bonds. With a competitive-type assay mode, the Hg(2+) in solution competed with the immobilized coating antigen for the limited McAb. Then, the second antibody labeled with HRP was introduced, and an effectively increased CL was obtained, which was ascribed to the catalytic activity of HRP for the luminol-PIP-H2O2 reaction. With increasing concentration of Hg(2+), the CL of this system decreases because less HRP is present in the CL reaction. At optimal conditions, the CL signal displayed a good linear relation toward Hg(2+) in the range of 0.05-200 ng mL(-1) with a detection limit (3σ) of 0.015 ng mL(-1). The immunosensor possessed high specificity, acceptable accuracy and reproducibility, and was examined in real samples with favorable results. This immunoassay will have intriguing application prospects for the determination of other heavy metal ions and environmental contaminants.