A MOF-to-MOF conversion assisted formation of hierarchical hollow Zn-Co_(1-x)S/C@C composite for efficient potassium-ion storage

Hollow structured composite can enhance the structural stability of metal sulfide anode by accommodating its volume variation,while the performance is still hindered by its poor electron/ion conductivity.Herein,we develop a hier-archical hollow structure to achieve superior electrochemical performance,from which a MOF-to-MOF conversion is utilized to generate hollow Zn-Co_(1-x)S/C composite followed with additional carbon coating layer.For potassium storage,as-prepared hollow Zn-Co1.xS/C@C composite displays high capacities of 375 mA h g^(-1)after 100 cycles at 0.2 A g^(-1)and 201 mA h g^(-1)after 500 cycles at 1 A g^(-1).Moreover,it also manifests outstanding rate capability of 200 mA h g^(-1)at 10 A g^(-1),outperforming hollow Co_(1-x)S@C and majority of the reported cobalt-based anodes.With illustration by kinetics analysis and theoretical calculation,both of Zn doping and internal carbon matrix are conductive to promote the charge transportation ability of Co_(1-x)S,thus accounting for the good cycling behavior and excellent rate capacity of hierarchical hollow Zn-Co1.xS/C@C composite.

Boosting Stable and Fast Potassium Storage of Iron Sulfide through Rational Yolk-Shell Design and Ni Doping

Metal sulfides have been regarded as promising anodes for potassium-ion batteries(PIBs)due to their high theoretical capacities,while the performance is limited by their intrinsic poor conductivity and large volume fluctuation during the insertion/extraction of large potassium ion.Herein,the battery performance of iron sulfide anode is significantly enhanced through yolk-shell(Y-S)structure design and nickel doping,aiming to realize good structure stability and superior electron/ion transportation.For potassium storage,as-prepared Y-S Ni-FeS_(2)@C shows excellent cyclic performance and sustains high capacities of 328 mA h g^(-1)after 100 cycles at 0.2 A g^(-1)and 226 mA h g^(-1)after 1000 cycles at 1 A g^(-1).Especially,it displays a superior rate capacity of 200 mA h g^(-1)at 20 A g^(-1),higher than that of Y-S FeS_(2)@C and most as-reported metal sulfide anodes for PIBs.The experimental analysis and theoretical calculation illuminate the effect of Ni-doping on decreasing the particle size of iron sulfide and enhancing the ion/electron transport ability,thus accounting for the exceptional rate capability of Y-S Ni-FeS_(2)@C composite.

Dual-function perovskite light-emitting/sensing devices for optical interactive display

Interactive display devices integrating multiple functions have become a development trend of display technology.The excellent luminescence properties of perovskite quantum dots(PQDs)make it an ideal luminescent material for the next generation of wide-color gamut displays.Here we design and fabricate dual-function light-sensing/displaying light-emitting devices based on PQDs.The devices can display information as an output port,and simultaneously sense outside light signals as an input port and modulate the display information in a non-contact mode.The dual functions were attributed to the device designs:(1)the hole transport layer in the devices also acts as the light-sensing layer to absorb outside light signals;(2)the introduced hole trapping layer interface can trap holes originating from the light-sensing layer,and thus tune the charge transport properties and the light-emitting intensities.The sensing and display behavior of the device can be further modulated by light signals with different time and space information.This fusion of sensing and display functions has broad prospects in non-contact interactive screens and communication ports.