Multifunctional Polypropylene Separator via Cooperative Modification and Its Application in the Lithium-Sulfur Battery.

The continuous shuttling of dissolved polysulfides between the electrodes is the primary cause for the rapid decay of lithium-sulfur batteries. Modulation of the separator-electrolyte interface through separator modification is a promising strategy to inhibit polysulfide shuttling. In this work, we develop a graphene oxide and ferrocene comodified polypropylene separator with multifunctionality at the separator-electrolyte interface. The graphene oxide on the functionalized separator could physically adsorb the polysulfide while the ferrocene component could effectively facilitate the conversion of the adsorbed polysulfide. Due to the combination of these beneficial functionalities, the separator exhibits an excellent battery performance, with a high reversible capacity of 409 mAh g-1 after 500 cycles at 0.2 C. We anticipate that the combinatorial separator functionalization proposed herein is an effective approach for improving the performance of lithium-sulfur batteries.

Application of sludge biochar combined with peroxydisulfate to degrade fluoroquinolones: Efficiency, mechanisms and implication for ISCO.

Peroxydisulfate (PDS) is increasingly used for in situ chemical oxidation (ISCO) of organic pollutants in groundwater, but the efficient and applicable activator is still scarce. In this study, sludge-derived biochar (SDBC) was prepared by pyrolysis to activate PDS, which could effectively degrade the fluoroquinolone antibiotics (FQs, levofloxacin, enrofloxacin, norfloxacin and ciprofloxacin). Compared with pig manure and corn straw derived biochar, SDBC showed higher efficiency in PDS activation. Singlet oxygen (1O2) was identified as the major reactive species, and the surface-bonded radicals also contributed to the FQs degradation. The selective oxidation of FQs by 1O2 was first reported, which followed the trend of enrofloxacin ~ levofloxacin > norfloxacin ~ ciprofloxacin. The CO and Fe2+ on SDBC were the dominant reactive sites for PDS activating. Products analysis revealed that FQs degradation proceeds via the cleavage of the piperazine ring, breaking of the quinolone ring, decarboxylation, and defluorination. Moreover, the tertiary amine of N (4) on enrofloxacin was more reactive towards singlet oxygen than the secondary amine of N (4) on ciprofloxacin, inducing the faster degradation and de-toxicity of enrofloxacin in the reaction system. SDBC showed high reusability in PDS activation and negligible metals leachates were detected. The column study proved the efficiency of PDS/SDBC in groundwater remediation.

Cellulose-based material in lithium-sulfur batteries: A review.

Lithium-sulfur (Li-S) battery is considered to be a promising energy storage system due to its high energy density and low cost. However, the commercialization of Li-S battery is hindered by several problems such as the insulating nature of active materials, notorious "shuttle effect" and damage of lithium dendrites. Cellulose-based materials have attracted widespread attention in the development of Li-S battery on account of their environmentally friendly nature, unique network structure, and possibility for chemical functionalization. This review summarizes the application of cellulose-based materials in Li-S batteries mainly as either the separator, the carbon material for binder assisted modification of separator or as carbon hosts for sulfur cathode and discusses the challenges that utilization of the cellulose-based materials could potentially encountered in Li-S battery. Perspectives regarding the future development of cellulose-based materials for Li-S battery are also discussed.