Lithium-sulfur batteries are a promising high energy output solution for substitution of traditional lithium ion batteries. In recent times research in this field has stepped into the exploration of practical applications. However, their applications are impeded by cycling stability and short life-span mainly due to the notorious polysulfide shuttle effect. In this work, a multifunctional sulfur host fabricated by grafting highly conductive Co 3 Se 4 nanoparticles onto the surface of an N-doped 3D carbon matrix to inhibit the polysulfide shuttle and improve the sulfur utilization is proposed. By regulating the carbon matrix and the Co 3 Se 4 distribution, N-CN-750@Co 3 Se 4 -0.1 m with abundant polar sites is experimentally and theoretically shown to be a good LiPSs absorbent and a sulfur conversion accelerator. The S/N-CN-750@ Co 3 Se 4 -0.1 m cathode shows excellent sulfur utilization, rate performance, and cyclic durability. A prolonged cycling test of the as-fabricated S/N-CN-750@Co 3 Se 4 -0.1 m cathode is carried out at 0.2 C for more than 5 months which delivers a high initial capacity of 1150.3 mAh g −1 and retains 531.0 mAh g −1 after 800 cycles with an ultralow capacity reduction of 0.067% per cycle, maintaining Coulombic efficiency of more than 99.3%. The reaction details are characterized and analyzed by ex situ measurements. This work highly emphasizes the potential capabilities of transition-metal selenides in lithium-sulfur batteries.

The sequence-specific detection of DNA hybridization has attracted considerable interest in numerous fields. Although traditional DNA biosensors have been widely explored due to their high sensitivity, it is still challenging to develop a low-cost, portable, disposable, fast, and easy-to-use DNA detection method for public use at home or in the field. To address these challenges, herein, we report a novel microfluidic photoelectrochemical (PEC) paper-based analytical platform, integrated with an internal chemiluminescent light source, a novel paper supercapacitor (PS) amplifier, and a terminal digital multi-meter (DMM) detector, for sensitive DNA detection using a graphene-modified porous Au-paper electrode as the working electrode to obtain enhanced PEC responses. The quantification mechanism of this strategy is based on the charging of this PS, which was constructed on a paper-based analytical platform through a simple "drawing and soaking" method, by the generated photocurrent. After a fixed period, the PS was automatically shorted under the control of a novel built-in fluidic delay-switch to output an instantaneously amplified current, which could be sensitively detected by the DMM. At optimal conditions, this paper-based analytical platform can detect DNA at concentrations at femtomolar level. This approach also shows excellent specificity toward single nucleotide mismatches.

A three-dimensional microfluidic origami glucose-air immuno-biofuel cell has been successfully demonstrated for the first time to implement self-powered, sensitive, and low-cost sandwich immunoassay for cancer markers based on the signal amplifications of a porous Au-paper electrode and Au nanoparticles attached to carbon nanotubes.

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