N-Doped C/ZnO-Modified Cu Foil Current Collector for a Stable Anode of Lithium-Metal Batteries

Long-lifetime aqueous Si-air batteries prepared by growing multi-dimensionally tunable ZIF-8 crystals on Si anodes

Si-air batteries have a high energy density, high theoretical voltage, and long lifetime, but they present a low anode utilization rate in a potassium hydroxide electrolyte. In this work, a ZIF-8 protective layer was prepared and modulated by a secondary growth method and then applied to protect the Si flat and Si nanowire (NW) anodes of a Si-air battery. By adjusting the conversion ratio, particle size, and crystallinity of ZIF-8 on the Si surface, the contact mode of the Si anode with water and OH- was controlled, thus achieving long-term corrosion and passivation resistance. Si NWs@ZIF-8 exhibited the highest average discharge voltage of 1.16 V, and the Si flat@ZIF-8 anode achieved the longest discharge time of 420 h. This work confirms that ZIF-8 acts as an anode protective layer to improve the properties of Si-air batteries and also provides valuable insights into the protection of Si anodes by MOFs.

Field-Assisted Regulation Induced by Cobalt-Doped ZnO for Dendrite-Free Lithium Metal Anodes

Lithium metal batteries are deemed as an optimal candidate for the next generation of durable energy storage devices. However, the growth of lithium dendrite and significant volume expansion pose as obstacles that impede the application of lithium metal batteries. In this work, a functional copper current collector was designed by coating it with Co-doped ZnO (Co/ZnO) to enhance the lithiophilicity through local electric fields and built-in magnetic fields induced by the ferromagnetic material. The incorporation of Co not only induces a local electric field and thus accelerating electron transfer, but also imparts the ferromagnetic behavior to ZnO, resulting in an internal magnetic field to regulate the dynamic trajectory. Profiting from the above advantages, the symmetric cells have excellent cycle stability in 1 mA cm-2 and 1 mAh cm-2 , maintaining ultra-low voltage for over 2000 h. This study provides a realizable pathway for next-generation current collector of copper modification.

Controllable and Homogeneous Lithium Electrodeposition via Lithiophilic Anchor Points

Uncontrollable growth of lithium (Li) dendrites and low Coulombic efficiency induce security hazards and a short cycling lifespan of Li metal batteries. In this study, well-aligned ZnO nanorods on a periodic three-dimensional (3D) copper mesh (CM) are modified as lithiophilic anchor points to regulate the electrodeposition behavior of Li metal anodes. The in situ generated LiZn/Li₂O arrays can efficiently guide the homogeneous Li electrodeposition along the nanorods. The porous structure of CM provides void space for the well-controlled lateral growth of Li starting from nanorod arrays. Moreover, the high surface area generated by both CM and the ZnO nanorods favors the charge transfer with low local current densities along the anode. Compared with bare Li anodes, Li-ZnO@CM anodes exhibited prolonged cycling stability for symmetric cells and superior capacity retention within Li/LiFePO₄ full cells, demonstrating the effective design principles of ZnO@CM for stabilizing Li metal batteries.