Armoring Black Phosphorus Anode with Stable Metal–Organic‑Framework Layer for Hybrid K‑Ion Capacitors

Potassium-ion capacitors(KICs)are promising for sustainable and eco-friendly energy storage technologies,yet their slow reaction kinetics and poor cyclability induced by large K-ion size are a major obstacle toward practical applications.Herein,by employing black phosphorus nanosheets(BPNSs)as a typical high-capacity anode material,we report that BPNS anodes armored with an ultrathin oriented-grown metal–organic-framework(MOF)interphase layer(BPNS@MOF)exhibit regulated potassium storage behavior for highperformance KICs.The MOF interphase layers as protective layer with ordered pores and high chemical/mechanical stability facilitate K ion diffusion and accommodate the volume change of electrode,beneficial for improved reaction kinetics and enhanced cyclability,as evidenced by substantial characterizations,kinetics analysis and DFT calculations.Consequently,the BPNS@MOF electrode as KIC anodes exhibits outstanding cycle performance outperforming most of the reported state-of-art KICs so far.

High-power,electronically controlled source of user-defined vortex and vector light beams based on a few-mode fiber amplifier

Optical angular momentum(OAM)-based structured light beams provide an additional degree of freedom for practical applications ranging from optical communication to laser-based material processing. Many techniques exist for generating such beams within laser sources and these primarily rely upon the use of specially designed optical components that limit laser power scaling and ready tunability of the topological charge and polarization of the output OAM beams. Here we show that some of these limitations can be overcome by employing a computer controlled reflective phase-only spatial light modulator to adaptively tailor the input(and subsequent output) beam wavefront and polarization in a few-mode fiber amplifier. In this way modal-coupling-induced beam distortion within the fiber amplifier can be mitigated and we are able to generate at will any desired supported spatial mode guided in the fiber, including conventional linearly polarized(LP) modes, scalar OAM modes, and cylindrical vector modes, at average powers >10 W and with a peak power of >11 kW. Our results pave the way to the realization of practical high-power structured laser sources with tunable chirality and polarization.

Templated spherical coassembly strategy to fabricate MoS_(2)/C hollow spheres with physical/chemical polysulfides trapping for lithium-sulfur batteries

Rational design of advanced polar hosts with high sulfur loading,facilitated ionic/electronic transport and effectively suppressed shuttling effect has great potential for high performance lithium-sulfur batteries,yet it remains challenging.Here we propose a novel templated spherical coassembly strategy to fabricate the MoS_(2)/C hollow spheres as an efficient sulfur host material.The unique hollow structure provides enough interior space for accommodating a substantial amount of sulfur,and effectively suppresses the diffusion of dissolved polysulfides by both physical confinement and chemical adsorption.Moreover,the ionic transport as well as the ability to mitigate volume variation upon cycling is also improved,thereby maximizing the utilization of sulfur.Owing to these merits,when evaluated as a sulfur host for lithiumsulfur batteries,the MoS_(2)/C hollow spheres exhibit appealing electrochemical performance with an impressive specific capacity of 1082 mA hg^(-1)at 0.1 C,excellent rate capability and superior cycling stability with a low fading rate of 0.04%per cycle.