Rationally designed hollow carbon nanospheres decorated with S,P co-doped NiSe2 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 NiSe2 nanoparticles are fabricated by ``drop and dry" and ``dissolving and precipitation" processes to form Ni(OH) (2) nanocrystals followed by annealing with S and P dopants to form nanoparticles. The resultant S,P-NiSe2/HC composite exhibits excellent cyclic performance with 131.6 mA h g(-1) at 1000 mA g(-1) after 3000 cycles for K+ storage and a capacity of 417.1 mA h g(-1) at 1000 mA g(-1) after 1000 cycles for Li+ storage. K-ion full cells are assembled and deliver superior cycling stability with a capacity 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 transportation and tolerates large volume variation for both K+ and Li+. Density functional theory calculations confirm that the S and P co-doping NiSe2 enables stronger adsorption of K+ ions and higher electrical conductivity that contributes to the improved electrochemical performance. (c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.