Overcoming Perovskite Corrosion and De-Doping Through Chemical Binding of Halogen Bonds Toward Efficient and Stable Perovskite Solar Cells

4-tert-butylpyridine(TBP)is an indispensable additive for the hole transport layer in highly efficient perovskite solar cells(PSCs),while it can induce corrosion decomposition of perovskites and de-doping effect of spiro-OMeTAD,which present huge challenge for the stability of PSCs.Herein,halogen bonds provided by 1,4-diiodotetrafluorobenzene(1,4-DITFB)are employed to bond with TBP,simultaneously preventing perovskite decomposition and eliminating de-doping effect of oxidized spiro-OMeTAD.Various characterizations have proved strong chemical interaction forms between 1,4-DITFB and TBP.With the incorporation of halogen bonds,perovskite film can maintain initial morphology,crystal structure,and light absorbance;meanwhile,the spiro-OMeTAD film shows a relatively stable conductivity with good charge transport property.Accordingly,the device with TBP complex exhibits significantly enhanced stability in N_(2) atmosphere or humidity environment.Furthermore,a champion power conversion efficiency of 23.03%is obtained since perovskite is no longer damaged by TBP during device preparation.This strategy overcomes the shortcomings of TBP in n-i-p PSCs community and enhances the application potential of spiro-OMeTAD in fabricating efficient and stable PSCs.

A crosslinking hydrogel binder for high-sulfur content S@pPAN cathode in rechargeable lithium batteries

High-energy density lithium-sulfur(Li-S) batteries have received intensive attention as promising energy storage system.Among diverse sulfur-based cathodes,sulfurized pyrolyzed poly(acrylonitrile)(S@pPAN)cathode delivered superior electrochemical performance.However,the sulfur content of S@pPAN is relatively low(<50 wt%),which significantly limits the energy density.Herein,a hydrogel SA-Cu binder was proposed with a crosslinking network constructed by Cu^(2+) ions.The introduction of Cu^(2+) ions enabled excellent electrochemical behaviors of S@pPAN cathode even with high sulfur content of 52.6 wt% via chemical interaction with sulfur and polysulfide.Moreover,a favorable cathode interphase was formed containing electrochemically active and conductive CuSx.S@pPAN/SA-Cu exhibited a high sulfur utilization of 85.3%,long cycling stability over 1000 cycles and remarkable capacity of 1200 mAh g_(s)^(-1) even at10 C.Furthermore,ascribed to the improved electrode structure,high-loading electrode(sulfur loading:4 mg cm^(-2)) displayed stable cycling with areal capacity of 5.26 mAh cm^(-2)(1315 mAh g_(s)^(-1)) after 40 cycles.This study provides new directions to prepare high-sulfur content and high-loading S@pPAN cathode for higher energy density.

Okra‑Like Multichannel TiO@NC Fibers Membrane with Spatial and Chemical Restriction on Shuttle‑Effect for Lithium–Sulfur Batteries

It is especially important to coordinately design the structure and composition of the host in lithium–sulfur batteries(LSBs)for improving its physicochemical adsorption and conversion of lithium polysulfide,which can alleviate the harmful shuttle effect.Herein,a self-supporting multichannel nitrogen-doped carbon fibers membrane embedded with TiO nanoparticles(TiO@NC)was constructed as the electrode for LSBs.The inner channels and the embedded TiO nanoparticles offer spatial confinement and chemical binding for polysulfides,respectively.Moreover,the TiO nanoparticles have abundant oxygen vacancies that promote the conversion of polysulfides.In addition,the nitrogen-doped carbon skeleton can not only serve as highly conductive transportation paths for electrons,but also integrate with the inner channels to sustain the morphology and bear volume expansion during cycling processes.Therefore,the fabricated self-supporting quadruple-channel TiO@NC ultrathin fibers electrode exhibits a high initial specific capacity of 1342.8 mAh g^(-1)at 0.5 C and high-rate capability of 505.8 mAh g^(-1)at 4.0 C.In addition,it maintains 696.0 mAh g^(-1)over 500 cycles with only 0.059%capacity decay per cycle at the high current density of 2.0 C.The multichannel configuration combined with TiO nanoparticles provides a synergetic design strategy for fabricating high-performance electrodes in LSBs.