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Graphene quantum dots (GQDs)-decorated hollow copper sulfide nanoparticles (CuS NPs) were developed as a multifunctional platform for controlled intracellular drug release and enhanced photothermal-chemotherapy. The CuS NPs were firstly synthesized to encapsulate anticancer drug doxorubicin (DOX) followed by the GQDs decoration on the surface of CuS NPs. The prepared NPs exhibited good crystal structure, uniform nanosize, excellent colloidal stability, high drug encapsulation and enhanced optical absorbance. Moreover, the drug release was successfully triggered from the DOX-CuS@GQDs NPs under high temperature and (near-infrared) NIR laser irradiation. Encouraged by this result, we moved to investigate the intracellular drug release behavior under NIR laser irradiation on MDA-MB-231 cells. The confocal images and flow cytometry analysis indicated a significant NIR-triggered DOX release within MDA-MB-231 cells after cellular uptake. Furthermore, the CuS NPs could readily convert light energy to heat to photothermally ablate the cancer cells under NIR laser irradiation, and the photothermal ablation effect was further enhanced by the capping of GQDs on CuS NPs. The combined photothermal therapy and chemotherapy of the prepared DOX-CuS@GQDs NPs also enabled a synergistic therapeutic effect on cancer cells. Therefore, the prepared DOX-CuS@GQDs NPs provided a novel promising platform for cancer therapy with controlled intracellular drug release and combined photothermal-chemotherapy. [ABSTRACT FROM AUTHOR]

Abstract Lithium ion capacitor (LIC) has been regarded as a promising device to combine the merits of high-energy lithium ion battery and high-power supercapacitor. The key challenge in developing high performance LIC is to achieve synergy between the high capacity of battery anode and the fast non-Faradaic reaction rate of capacitive cathode without compromising energy density. Here, we report 3D interconnected Fe 3 O 4 @C core@shell nanocomposites with enhanced lithium storage reaction kinetics as an anode material of LIC. Chitosan, a renewable biopolymer with rich functional groups, has been utilized as both structural directing agent and carbon precursor to assist the synthesis of Fe 3 O 4 @C composites, which have small particle size and an in-situ formed carbon coating layer. The carbon coating can not only dramatically improve the electronic conductivity, but also buffer the large volume expansion/contraction of Fe 3 O 4 during lithiation/delithiation. The Fe 3 O 4 @C composites show a reversible capacity of 1116.1 mA h g−1 at 0.1 A g−1 and 587.2 mA h g−1 at 2 A g−1, as well as stable capacity retention over cycling. Furthermore, the hybrid device based on Fe 3 O 4 @C composites achieves a specific energy of 110.1 Wh kg−1 at a specific power of 250 W kg−1, demonstrating promising application of the reported hybrid systems. Graphical abstract A lithium ion battery and supercapacitor hybrid device has been constructed with novel designed 3D interconnected Fe 3 O 4 @C anode prepared using chiotsan biopolymer, which combines high energy density and high power density simultaneously. The hybrid device achieves an exceptional energy density of 110.1 Wh kg−1 at a specific power of 250 W kg−1 with outstanding capacity retention. Image 1 [ABSTRACT FROM AUTHOR]

Li ion capacitors (LICs) are emerging as a promising device to integrate the high power density of supercapacitors with the high energy density of Li ion batteries. However, the insufficient specific capacity of the conventional capacitive electrode presents a great challenge in achieving high energy density for LICs. Herein, we demonstrate the synthesis of hierarchical porous carbon with an extremely large specific surface area of 3898 m2 g−1 and an improved graphitization degree by using egg white biomass as a precursor and NaCl as a template, in which dual functional NaCl served both as a macropore creating template and a graphitic catalyst to enhance the graphitization degree. With rational design, the developed porous carbon exhibits a noticeably enhanced specific capacity of 118.8 mA h g−1 at 0.1 A g−1 with excellent rate capability and improved cycling stability over 4000 cycles in an organic Li ion conducting electrolyte. Furthermore, the obtained porous carbon was employed as a cathode paired with a Fe3O4@C anode for LIC applications, which delivers an integrated high energy density of 124.7 W h kg−1 and a power density of 16 984 W kg−1 as well as a superior capacity retention of 88.3% after 2000 cycles at 5 A g−1, demonstrating the promising application as potential electrode candidates for efficient energy storage systems. [ABSTRACT FROM AUTHOR]

Sodium-ion hybrid capacitors (NIHC) with sodium ion battery type anodes and supercapacitor type cathodes are emerging as an attractive energy storage device due to the integration of high energy, high power and long lifetime. However, the battery type electrodes usually exhibit sluggish reaction kinetics than capacitor type cathodes due to slow Na ion insertion and extraction, which greatly hinders the rate performance. In this paper, carbon coated MoS 2 nanosheets are vertically grown on carbon cloth (CC) substrate using a hydrothermal reaction followed by calcination. The expanded interlayer distance of the MoS 2 ensures high ionic mobility while the highly conductive CC not only provides a self-supporting structure without the addition of insulative binder and additional conductive additive, but also effectively prevents the restacking of the MoS 2 sheets during cycling. Thus the architecture delivers a high area capacity of 0.511 mAh cm −2 at a current density of 0.2 mA cm −2 and a stable capacity retention of 83.3% after 200 cycles at 1 mA cm −2 . Furthermore, NIHC constructed with above anode delivers a high areal energy density of 1.22 mWh cm −2 at a power of 0.76 mW cm −2 , demonstrating an excellent energy-power delivery. [ABSTRACT FROM AUTHOR]

Co-axial silicon-coated carbon nanotubes (CNTs/Si) were successfully synthesized via a hydrothermal method. Sandwich-like carbon-coated CNTs/Si were obtained by an additional carbon coating. The as-prepared materials show superior cycling performance as anode materials in lithium ion batteries with a current density as high as 500 mA g−1 with no observable structural changes during the charge/discharge process. In addition, stable reversible discharge capacities as high as 1508.5 mA h g−1 after 1000 cycles were obtained. At higher current densities of 1 A g−1 and 2 A g−1, the CNTs/Si/C nanotubes also showed ideal cycling performance with reversible discharge capacities of 1216.6 mA h g−1 and 932.2 mA h g−1, respectively. The sandwich-like hollow tube structure of CNTs/Si/C not only alleviates the volume change during cycling, but also facilitates Li-ion and electron transport, and stabilizes the SEI layer. These results suggest that sandwich-like CNTs/Si/C nanotubes are a promising anode material for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Na 3 V 2 (PO 4 ) 3 is considered as one of the most promising cathode materials for SIB, electrodes through exploiting unconventional and relatively expensive vanadium salts or carbon sources. For the latter, the obtained superior rate performance is generally obtained at relatively high content of the carbon additives. A carbon-coated sodium ion containing vanadium phosphate, Na 3 V 2 (PO 4 ) 3 , is prepared by a simple sequentially-processed method. The sequentially-processed method is potential for mass-production and preparation of other high-quality vanadium-based electrode materials. A special dissolution sequence leads to an un-precipitated solution, which is used to produce an amorphous-state precursor. The carbon mass fraction of sequentially-processed Na 3 V 2 (PO 4 ) 3 is estimated to be less than 2% measured by thermo-gravimetric analyzer. Electrochemical performance of sequentially-processed Na 3 V 2 (PO 4 ) 3 is examined as cathode material for aprotic sodium ion battery. The sequentially-processed Na 3 V 2 (PO 4 ) 3 delivers 113 mA h g −1 with a flat voltage plateau at 3.4 V vs sodium metal. The simple sequentially-processed method also endows excellent rate capacity and cyclability to sequentially-processed Na 3 V 2 (PO 4 ) 3 at the voltage window of 2.8–3.8 V. We further investigate cyclic and rate performance of sequentially-processed Na 3 V 2 (PO 4 ) 3 as a high-capacity cathode material with a widened voltage window of 1–4 V vs Na + /Na. A capacity of more than 210 mA h g −1 can be delivered with appearance of another additional voltage plateau at 1.6 V but the capacity quickly fades away after dozens of cycles. The result validates the potential of Na 3 V 2 (PO 4 ) 3 in reaching high cathode capacity (> 200 mA h g −1 ) and also calls for new structure design to better accommodate the intercalation of sodium ions and new binder materials that can tolerate a larger degree of electrode expansion. [ABSTRACT FROM AUTHOR]