Metallic Zn is an appealing anode for aqueous Zn-ion batteries, but it suffers from corrosion and Zn dendrites. In this work, we develop a nonstoichiometric silicon nitride (SiN x ) film with specific defect sites, i.e., Si dangling bonds (Si DBs), to modify the surface property and thus to enhance the stability of Zn anodes. The Si DBs, together with zincophilic N sites with strong Zn affinity, are able to uniformly distribute Zn2+ ions on the anodes, enabling an even Zn deposition. Meanwhile, the electrochemically inert SiN x films can also suppress the side reactions to achieve a high Coulombic efficiency. As a result, the SiN x @Zn symmetrical battery possesses a long lifespan of more than 4600 h at 1 mA cm–2. Our work highlights the importance of defect engineering of protective layers in inhibiting the uncontrollable growth of Zn dendrites for constructing high-performance Zn anodes.

Secondary aqueous zinc-ion batteries (ZIBs) are considered as one of the promising energy storage devices, but their widespread application is limited by the Zn dendrite issues. In this work, we propose a rational design of surface protective coatings to solve this problem. Specifically, a silver (Ag) nanoparticle embedded amorphous AlN matrix (AlN/Ag) protective layer is developed. The former would alloy in situ with Zn to form AgZn3 alloy sites, which subsequently induce the Zn deposition with preferred (002) facets. The latter can effectively alleviate the structural expansion during repeated Zn plating/stripping. Consequently, the delicately designed AlN/Ag@Zn anode delivers an enhanced stability with a long lifespan of more than 2600 h at 1 mA cm–2 and 1 mAh cm–2. Moreover, the AlN/Ag@Zn||Mn1.4V10O24·nH2O full batteries can be operated for over 8000 cycles under 5 A g–1. Our work not only suggests a promising Zn anode protective coating but also provides a general strategy for the rational design of surface protective layers for metal anodes.

Titanium (Ti) and its alloys have been extensively used as implant materials in clinical practice due to their high corrosion resistance, light weight and excellent biocompatibility. However, the insufficient intrinsic osteogenic capacity of Ti and its alloys impedes bone repair and regeneration, and implant-related infection or inflammation remains the leading cause of implant failure. Bacterial infections or inflammatory diseases constitute severe threats to human health. The physicochemical properties of the material are critical to the success of clinical procedures, and the doping of Cu into Ti implants has been confirmed to be capable of enhancing the bone repair/regeneration, angiogenesis and antibacterial capability. This review outlines the recent advances in the design and preparation of Cu-doped Ti and Ti alloy implants, with a special focus on various methods, including plasma immersion implantation, magnetron sputtering, galvanic deposition, microarc oxidation and sol-gel synthesis. More importantly, the antibacterial and mechanical properties as well as the corrosion resistance and biocompatibility of Cu-doped Ti implants from different methods are systematically reviewed, and their prospects and limitations are also discussed.