High-yield red phosphorus sponge mediated robust lithium-sulfur battery

Although lithium-sulfur(Li-S)batteries with high specific energy exhibit great potential for next-generation energy-storage systems,their practical applications are limited by the growth of Li dendrites and lithium polysulfides(LiPSs)shuttling.Herein,a highly porous red phosphorus sponge(HPPS)with well distributed pore structure was efficiently prepared via a facile and largescale hydrothermal process for polysulfides adsorption and dendrite suppression.As experimental demonstrated,the porous red phosphorus modified separator with increased active site greatly promotes the chemisorption of LiPSs to efficiently immobilize the active sulfur within the cathode section,while Li metal anode activated by Li_(3)P interlayer with abundant ionically conductive channels significantly eliminates the barrier for uniform Li^(+)permeation across the interlayer,contributing to the enhanced stability for both S cathode and Li anode.Mediated by the HPPS,long-term stability of 1,200 h with minor voltage hysteresis is achieved in symmetric cells with Li_(3)P@Li electrode while Li-S half-cell based on HPPS modified separator delivers an outperformed reversibility of 783.0 mAh·g^(−1)after 300 cycles as well as high-rate performance of 694.5 mAh·g^(−1)at 3 C,which further boosts the HPPS tuned full cells in practical S loading(3 mg·cm^(−2))and thin Li3P@Li electrode(100μm)with a capacity retention of 71.8%after 200 cycles at 0.5 C.This work provides a cost-effective and metal free mediator for simultaneously alleviating the fundamental issues of both S cathode and Li anode towards high energy density and long cycle life Li-S full batteries.

Carbon dots for ultrastable solid-state batteries

Among the solid electrolytes for solid-state Li batteries,polymer electrolytes are actively explored on the basis of the good interfacial contact and easy making,while it is still constrained by slow ionic transport and low lithium ion transference number.Herein,functional carbon dots-based Li+conductor(CD-Li)is designed to improve the dynamics and selectivity of Li+transport in polyethylene oxide(PEO)electrolyte.High ionic conductivity(1.0×10^(−4) S/cm,25℃)and Li+transference number(0.60)were successfully achieved within the CD‐Li‐based PEO composite electrolyte,which could be attributed to the enhanced chain movement and the limited motion of anion.Moreover,the characteristics of big volume of individual anions of CD-Li can provide more free Li^(+).As well,benefiting from the existence of F atom in the CD-Li,in-situ constructed LiF-containing interfacial layer is in favor of maintaining the interface stability and facilitating the rapid transmission of Li ions.The composite electrolyte with CD-Li can address the ionic conductivity issues accompanied with strengthening the interfacial stability.The distinctive composite electrolyte realizes the stable cycle performance for Li/LiFePO_(4) and Li/LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)batteries.The exploration of multifunctional carbon dot fillers provides new ideas for the efficient development of composite electrolytes.