On the Stability of NaO₂ in Na–O₂ Batteries

Na–O₂ batteries are regarded as promising candidates for energy storage. They have higher energy efficiency, rate capability, and chemical reversibility than Li–O₂ batteries; in addition, sodium is cheaper and more abundant compared to lithium. However, inconsistent observations and instability of discharge products have inhibited the understanding of the working mechanism of this technology. In this work, we have investigated a number of factors that influence the stability of the discharge products. By means of in operando powder X-ray diffraction study, the influence of oxygen, sodium anode, salt, solvent, and carbon cathode were investigated. The Na metal anode and an ether-based solvent are the main factors that lead to the instability and decomposition of NaO₂ in the cell environment. This fundamental insight brings new information on the working mechanism of Na–O₂ batteries

Hydrogen Peroxide-Responsive Nanoprobe Assists Circulating Tumor Cell Identification and Colorectal Cancer Diagnosis

In the clinic, numeration of circulating tumor cells (CTCs) plays a critical role in cancer diagnosis and treatment, but conventional CTC identification and counting that rely on specific antibodies to characterize a cell’s surface antigens are costive and with limitations. Importantly, false positive or negative results may occur due to the high heterogeneity and epithelial-mesenchymal transition (EMT) of CTCs. Herein we demonstrate a novel and effective CTC detecting nanoprobe that could rapidly respond to the high level of endogenous H₂O₂ of CTCs and report the signal through fluorescence emission. Briefly, a hydrophobic coumarin–benzene boronic acid pinacol ester (Cou-Bpin) was grafted onto hydrophilic glycol chitosan (GC) to form an amphiphilic molecule, which further assembled into micellar nanoparticles in aqueous solution. This new nanoprobe was highly sensitive to H₂O₂ with a detection limit of 0.1 μM and could rapidly enter the cells within 30 min. Upon exposure to intracellular H₂O₂, the nanoprobe exhibited remarkable one-photon and two-photon luminescent characteristics, which were suitable for imaging of endogenous H₂O₂ of various human colorectal cancer cells and assist the identification of CTCs. Compared to a conventional CTC counting assay, the nanoprobe-based CTC numeration could overcome the false-negative findings due to the low expression of cytokeratin 19 (CK19). In a clinic test, CTC counting results based on the new nanoprobe match better to the postoperative pathological results of four clinic patients who had colorectal cancer at different stages

Amorphous Chloride Solid Electrolytes with High Li-Ion Conductivity for Stable Cycling of All-Solid-State High-Nickel Cathodes

Solid electrolytes (SEs) are central components that enable high-performance, all-solid-state lithium batteries (ASSLBs). Amorphous SEs hold great potential for ASSLBs because their grain-boundary-free characteristics facilitate intact solid–solid contact and uniform Li-ion conduction for high-performance cathodes. However, amorphous oxide SEs with limited ionic conductivities and glassy sulfide SEs with narrow electrochemical windows cannot sustain high-nickel cathodes. Herein, we report a class of amorphous Li–Ta–Cl-based chloride SEs possessing high Li-ion conductivity (up to 7.16 mS cm–1) and low Young’s modulus (approximately 3 GPa) to enable excellent Li-ion conduction and intact physical contact among rigid components in ASSLBs. We reveal that the amorphous Li–Ta–Cl matrix is composed of LiCl43–, LiCl54–, LiCl65– polyhedra, and TaCl6– octahedra via machine-learning simulation, solid-state 7Li nuclear magnetic resonance, and X-ray absorption analysis. Attractively, our amorphous chloride SEs exhibit excellent compatibility with high-nickel cathodes. We demonstrate that ASSLBs comprising amorphous chloride SEs and high-nickel single-crystal cathodes (LiNi0.88Co0.07Mn0.05O2) exhibit ∼99% capacity retention after 800 cycles at ∼3 C under 1 mA h cm–2 and ∼80% capacity retention after 75 cycles at 0.2 C under a high areal capacity of 5 mA h cm–2. Most importantly, a stable operation of up to 9800 cycles with a capacity retention of ∼77% at a high rate of 3.4 C can be achieved in a freezing environment of −10 °C. Our amorphous chloride SEs will pave the way to realize high-performance high-nickel cathodes for high-energy-density ASSLBs

Amorphous Chloride Solid Electrolytes with High Li-Ion Conductivity for Stable Cycling of All-Solid-State High-Nickel Cathodes

Solid electrolytes (SEs) are central components that enable high-performance, all-solid-state lithium batteries (ASSLBs). Amorphous SEs hold great potential for ASSLBs because their grain-boundary-free characteristics facilitate intact solid–solid contact and uniform Li-ion conduction for high-performance cathodes. However, amorphous oxide SEs with limited ionic conductivities and glassy sulfide SEs with narrow electrochemical windows cannot sustain high-nickel cathodes. Herein, we report a class of amorphous Li–Ta–Cl-based chloride SEs possessing high Li-ion conductivity (up to 7.16 mS cm–1) and low Young’s modulus (approximately 3 GPa) to enable excellent Li-ion conduction and intact physical contact among rigid components in ASSLBs. We reveal that the amorphous Li–Ta–Cl matrix is composed of LiCl43–, LiCl54–, LiCl65– polyhedra, and TaCl6– octahedra via machine-learning simulation, solid-state 7Li nuclear magnetic resonance, and X-ray absorption analysis. Attractively, our amorphous chloride SEs exhibit excellent compatibility with high-nickel cathodes. We demonstrate that ASSLBs comprising amorphous chloride SEs and high-nickel single-crystal cathodes (LiNi0.88Co0.07Mn0.05O2) exhibit ∼99% capacity retention after 800 cycles at ∼3 C under 1 mA h cm–2 and ∼80% capacity retention after 75 cycles at 0.2 C under a high areal capacity of 5 mA h cm–2. Most importantly, a stable operation of up to 9800 cycles with a capacity retention of ∼77% at a high rate of 3.4 C can be achieved in a freezing environment of −10 °C. Our amorphous chloride SEs will pave the way to realize high-performance high-nickel cathodes for high-energy-density ASSLBs

Amorphous Chloride Solid Electrolytes with High Li-Ion Conductivity for Stable Cycling of All-Solid-State High-Nickel Cathodes

Solid electrolytes (SEs) are central components that enable high-performance, all-solid-state lithium batteries (ASSLBs). Amorphous SEs hold great potential for ASSLBs because their grain-boundary-free characteristics facilitate intact solid–solid contact and uniform Li-ion conduction for high-performance cathodes. However, amorphous oxide SEs with limited ionic conductivities and glassy sulfide SEs with narrow electrochemical windows cannot sustain high-nickel cathodes. Herein, we report a class of amorphous Li–Ta–Cl-based chloride SEs possessing high Li-ion conductivity (up to 7.16 mS cm–1) and low Young’s modulus (approximately 3 GPa) to enable excellent Li-ion conduction and intact physical contact among rigid components in ASSLBs. We reveal that the amorphous Li–Ta–Cl matrix is composed of LiCl43–, LiCl54–, LiCl65– polyhedra, and TaCl6– octahedra via machine-learning simulation, solid-state 7Li nuclear magnetic resonance, and X-ray absorption analysis. Attractively, our amorphous chloride SEs exhibit excellent compatibility with high-nickel cathodes. We demonstrate that ASSLBs comprising amorphous chloride SEs and high-nickel single-crystal cathodes (LiNi0.88Co0.07Mn0.05O2) exhibit ∼99% capacity retention after 800 cycles at ∼3 C under 1 mA h cm–2 and ∼80% capacity retention after 75 cycles at 0.2 C under a high areal capacity of 5 mA h cm–2. Most importantly, a stable operation of up to 9800 cycles with a capacity retention of ∼77% at a high rate of 3.4 C can be achieved in a freezing environment of −10 °C. Our amorphous chloride SEs will pave the way to realize high-performance high-nickel cathodes for high-energy-density ASSLBs