Novel Nanosized Adsorbing Composite Cathode Materials for the Next Generational Lithium Battery

A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon （HSAAC） under certain conditions. The physical and chemical per- formances of the novel carbon-sulfur nano-composite were characterized by scanning electron microscopy （SEM）, Brunauer-Emmett-Teller （BET） and X-ray diffraction （XRD）. The electrochemical performances of nano-composite were characterized by charge-discharge characteristic, cyclic voltammetry and electrochemical impendence spectroscopy （EIS）. The experimental results indicate that the electrochemical capability of nano- composite material was superior to that of traditional S-containing composite material. The cathode made by carbon-sulfur nano-composite material shows a good cycle ability and a high specific charge-discharge capacity. The HSAAC shows a vital role in adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for a sulfur cathode and prevents the shuttle behavior of the lithium-sulfur battery.

Electrochemical Impedance Spectroscopy Study on Novel Carbon-Sulfur Nano-Composite Cathodes in Lithium Rechargeable Batteries

Carbon-sulfur nano-composite cathodes for lithium rechargeable batteries were investigated by electrochemical impedance spectroscopy (EIS). The novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) in certain conditions. Equivalent circuits were used to fit the spectra at different discharge states. The variations of impedance spectra, charge-transfer resistance and double layer capacitance were discussed. The changes of EIS with potential were analyzed based on a plausible electrical equivalent circuit model, and some parameters were measured and analyzed about electrochemical performance and state of charge and discharge of the electrode. The good accuracy in fitting values of the model to the experimental data indicates that the mathematical model gives out a satisfying description upon the mechanism of high rate of capacity fade in lithium-sulfur battery.

NIR-II light triggered burst-release cascade nanoreactor for precise cancer chemotherapy

The current strategy of co-delivering copper ions and disulfiram(DSF)to generate cytotoxic CuET faces limitations in achieving rapid and substantial CuET production,specifically in tumor lesions.To overcome this challenge,we introduce a novel burst-release cascade reactor composed of phase change materials(PCMs)encapsulating ultrasmall Cu_(2-x)Se nanoparticles(NPs)and DSF(DSF/Cu_(2-x)Se@PCM).Once triggered by second near-infrared(NIR-II)light irradiation,the reactor swiftly releases Cu_(2-x)Se NPs and DSF,enabling catalytic reactions that lead to the rapid and massive production of Cu_(2-x)Se-ET complexes,thereby achieving in situ chemotherapy.The mechanism of the burst reaction is due to the unique properties of ultrasmall Cu_(2-x)Se NPs,including their small size,multiple defects,and high surface activity.These characteristics allow DSF to be directly reduced and chelated on the surface defect sites of Cu_(2-x)Se,forming Cu_(2-x)Se-ET complexes without the need for copper ion release.Additionally,Cu_(2-x)Se-ET has demonstrated a similar(to CuET)anti-tumor activity through increased autophagy,but with even greater potency due to its unique two-dimensional-like structure.The light-triggered cascade of interlocking reactions,coupled with in situ explosive generation of tumor-suppressive substances mediated by the size and valence of Cu_(2-x)Se,presents a promising approach for the development of innovative nanoplatforms in the field of precise tumor chemotherapy.