Cocoon Silk-Derived, Hierarchically Porous Carbon as Anode for Highly Robust Potassium-Ion Hybrid Capacitors

Potassium-ion hybrid capacitors(KIHCs) have attracted increasing research interest because of the virtues of potassium-ion batteries and supercapacitors.The development of KIHCs is subject to the investigation of applicable K+storage materials which are able to accommodate the relatively large size and high activity of potassium.Here,we report a cocoon silk chemistry strategy to synthesize a hierarchically porous nitrogen-doped carbon(SHPNC).The as-prepared SHPNC with high surface area and rich N-doping not only offers highly efficient channels for the fast transport of electrons and K ions during cycling,but also provides sufficient void space to relieve volume expansion of electrode and improves its stability.Therefore,KIHCs with SHPNC anode and activated carbon cathode afford high energy of 135 Wh kg-1(calculated based on the total mass of anode and cathode),long lifespan,and ultrafast charge/slow discharge performance.This study defines that the KIHCs show great application prospect in the field of high-performance energy storage devices.

The stability of inorganic perovskite solar cells:from materials to devices

Inorganic halide perovskite solar cells(IHPSCs)have become one of the most promising research hotspots due to to the excellent light and thermal stabilities of inorganic halide perovskites(IHPs).Despite rapid progress in cell performance in very recent years,the phase instability of IHPs easily occurs,which will remarkably influence the cell efficiency and stability.Much effort has been devoted to solving this issue.In this review,we focus on representative progress in the stability from IHPs to IHPSCs,including(i)a brief introduction of inorganic perovskite materials and devices,(ii)some new additives and fabrication methods,(iii)thermal and light stabilities,(iv)tailoring phase stability,(v)optimization of the stability of inorganic perovskite solar cells and(vi)interfacial engineering for stability enhancement.Finally,perspectives will be given regarding future work on highly efficient and stable IHPSCs.This review aims to provide a thorough understanding of the key influential factors on the stability of materials to highly efficient and stable IHPSCs.

Reconfiguring perovskite interface via R4NBr addition reaction toward efficient and stable FAPbI3-based solar cells

Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite interface by the interaction between a series of quaternary ammonium bromides(QAB)and lead—halide(Pb—X)octahedrons.Bromide—iodide substitution reaction or R4NBr addition reaction may occur on the perovskite surface,which is related to the steric hindrance of quaternary ammonium cations.On this basis,the perovskite surface morphology,band structure,growth orientation and defect states are reconstructed via the R4NBr addition reaction.This ordered lead—halide adduct could effectively repair the imperfect perovskite/hole transportation layer interface to suppress non-radiative recombination and ion migration toward ultralong carrier lifetime surpassing 10µs.The resulting perovskite solar cells yield the efficiency of 23.89%with steady-state efficiency of 23.70%.The passivated cells can sustain 86%of initial efficiency after 200-h operation,which is attributed to the passivation effect and hydrophobic characteristics.This work provides an avenue for reconfiguring perovskite surface by QABs.