Rationally designed hollow carbon nanospheres decorated with S,P co-doped NiSe_(2) nanoparticles for high-performance potassium-ion and lithium-ion batteries

Hollow nanostructures with external shells and inner voids have been proved to greatly shorten the transport distance of ions/electrons and buffer volume change,especially for the large-sized potassium-ions in secondary batteries.In this work,hollow carbon(HC) nanospheres embedded with S,P co-doped NiSe_(2)nanoparticles are fabricated by "drop and dry" and "dissolving and precipitation" processes to form Ni(OH)2nanocrystals followed by annealing with S and P dopants to form nanoparticles.The resultant S,P-NiSe_(2)/HC composite exhibits excellent cyclic performance with 131.6 mA h g^(-1)at1000 mA g^(-1)after 3000 cycles for K^(+)storage and a capacity of 417.1 mA h g^(-1)at 1000 mA g^(-1)after1000 cycles for Li^(+)storage.K-ion full cells are assembled and deliver superior cycling stability with a ca pacity of 72.5 mA h g^(-1)at 200 mA g^(-1)after 500 cycles.The hollow carbon shell with excellent electrical conductivity effectively promotes the transporta tion and tolerates large volume variation for both K^(+)and Li^(+).Density functional theory calculations confirm that the S and P co-doping NiSe_(2) enables stronger adsorption of K^(+)ions and higher electrical conductivity that contributes to the improved electrochemical performance.

Self-supporting Co_(0.85)Se nanosheets anchored on Co plate as highly efficient electrocatalyst for hydrogen evolution reaction in both acidic and alkaline media

Electrocatalytic water splitting via hydrogen evolution reaction(HER)represents one of promising strategies to gain hydrogen energy.In current work,self-supporting Co_(0.85)Se nanosheets network anchored on Co plate(Co_(0.85)Se NSs@Co)is fabricated by employing easily tailorable Co metal plate as the source conductive substrate.The scalable dealloying and hydrothermal selenization strategy was employed to build one layer of three dimensional interlinking Co_(0.85)Se nanosheets network on the surface of Co plate.Benefiting from bulky integrated architecture and rich active sites,the as-made Co_(0.85)Se NSs@Co exhibits superior electrocatalytic activity and long-term catalytic durability toward HER.It only requires lower overpotentials of 121 and 162 mV to drive the current density of 10 mA·cm^(−2)for hydrogen evolution in 0.5 M H_(2)SO_(4)and 1 M KOH solution.Especially,no evident activity decay occurs upon 1,500 cycles or continuous test for 20 h at 10 mA·cm^(−2)in both acidic and alkaline electrolytes.With the merits of exceptional performances,scalable production,and low cost,the self-supporting Co0.85Se NSs@Co holds prospective application potential as stable and binder-free electrocatalysts for hydrogen generation in a wide range of electrolyte.

Call for Papers Special Issue on High-Performance Computing for the Next Decade

The publication of Tsinghua Science and Technology was started in 1996.Since then,it has been an international academic journal sponsored by Tsinghua University and published bimonthly.This journal aims at presenting the state-of-the-art scientific achievements in computer science and other IT fields.From 2012,the journal enters into IEEE Xplore