Magnesium(Mg),which offers an ideal combination of numerous appealing properties,such as low density,low cost,high hydrogen storage capacity,good biocompatibility,and excellent electromagnetic shielding capacity,among others,has been the key candidate for use in the future of functional materials [1].Many endeavors have been carried out for the development of Mg-based functional materials.Concerning energy saving and environmental protection,Mg-based hydrogen(H2)storage materials have been developed rapidly due to their high storage density,reversibility and recyclability [2].Much progress has been achieved in the last few decades,which mainly focuses on increasing the thermodynamic and kinetic properties of Mg-based materials while retaining the high H2storage capacity.Rechargeable Mg batteries are considered as a promising alternative to lithium(Li)in the field of ion-transfer batteries [3,4].The selection of suitable cathodes for Mg ion insertion,de-insertion,and preparation of Mg-ionconducting electrolytes with adequate ionic conductivity have all been critical topics in previous studies [5].In terms of biodegradable implant materials,Mg alloys have pronounced merits because they naturally exist in bone tissue and their Young’s moduli are close to that of human bone [6–8].For their application in implant materials,research has focused on the controlling of the evolution and degradation rates of H2in the physiological environment.Mg alloys also show excellent damping capacity and electromagnetic shielding performance [9].The current concern is balancing the damping capacity with electromagnetic shielding performance and mechanical properties,for which alloying,heat treatment,plastic deformation,and adding reinforcements have all already been utilized in the literature [10,11].

In this special issue on Mg-based functional materials,the editors have selected the latest innovative research in the fields of Mg-based hydrogen storage materials,Mg batteries,biodegradable implant materials,and Mg alloys with developed shielding effectiveness.This issue includes 26 contributions from countries including Germany,the United States,France,China,New Zealand,Australia,Romania,India,Mexico,Columbia,Iran,Korea,and Russia.To highlight the new frontiers,challenges,and perspectives,5 reviews are included to help readers gain a comprehensive and systematic understanding in these specific fields.Additionally,much strong international cooperation is reflected among the authors in many of the publications.

On behalf of the editors,we would like to thank all authors that participated in this special issue and we greatly appreciate all the contributors who support our publication and made this special issue possible.We hope readers may find this issue interesting,innovative,and inspiring under its selected contents.