Biodegradable metals (BMs) have shown significant potential for applications in the field of orthopedic implants. These materials gradually degrade after implantation, eventually disappear without residue, provide necessary mechanical support during degradation, and closely integrate with bone tissues. Fe-based BMs are particularly notable for their good mechanical properties and biocompatibility. However, their slow degradation rate is a limitation. The emergence of Mn-incorporated Fe-based alloys (Fe-Mn alloys) offers the possibilities for addressing issues of slow degradation rate and incompatibility of magnetic resonance imaging (MRI) for Fe alloys. This review summarizes the advantages of Fe-Mn alloys as orthopedic implants, and the cutting-edge advances in degradation, mechanical and magnetic properties, and osteogenic performance. The cytotoxicity issue is addressed for the porous structured Fe-Mn alloys caused by the enrichment of manganese ions, and thus the main challenge and the development are involved for the Fe-Mn alloys to achieve a balance among biocompatibility, structure, and degradation rate. Also the perspectives are proposed for Fe-Mn alloys as orthopedic implants.

Potassium-ion batteries (PIBs) are highly attractive and are promising energy storage technology because of their cost-effectiveness, superior safety, environmental friendliness, as well as high standard K/K⁺ redox potential, and abundance and low cost of potassium. Transition metal disulfides (TMDs) have a wide interlayer spacing that is attractive as a K⁺ storage site in PIBs. Moreover, TMDs have high reversible capacity and are low cost. Nevertheless, they have not been extensively studied. The practical application of TMDs is impeded by their fast capacity fading and poor rate performance. More well-focused research should aim for the commercialization of TMDs in PIBs. This paper reviews (a) the main strategies to enhance the application of TMDs in PIBs; (b) the recent development of using TMDs such as MoS₂, WS₂, and SnS₂ as electrode materials for PIBs, including their structure, performance, and defects, as well as the methods to alleviate their defects; (c) the associated electrochemical processes; and (d) the critical issues, challenges, and prospects.

The direct industrial importance of the corrosion resistance in WE43 is best emphasized by its extensive use in the automotive, aerospace and electronic industries where weight reduction is a necessary requirement. In this work, the corrosion especially the filiform corrosion in a 3.5 wt.% NaCl solution and their dependence on the Zr distribution for WE43 were studied by weight loss tests, hydrogen evolution tests, electrochemical measurements and microscopic analyses. The Zr distribution significantly influenced the initiation and propagation of the filiform corrosion, and accordingly significantly influenced the corrosion rate. WE43 with a cluster Zr distribution displayed filiform corrosion throughout the entire surface with an irregular network distribution of filaments. WE43 with a uniform line Zr distribution exhibited only a few examples of linear filiform corrosion. WE43 with a dispersive Zr distribution exhibited no filiform corrosion. The stability of the corrosion film was responsible for the filiform corrosion. Anodic polarisation promoted the initiation and progression of the filiform corrosion, while cathodic polarisation had an inhibiting effect on the filiform corrosion. The serrated interface of the filiform corrosion increased the contact area between the substrate and the corrosive medium, and hence increased the corrosion rate.