High Entropy Induced Local Charge Enhancement Promotes Frank–Van der Merwe Growth for Dendrite‐Free Potassium Metal Batteries

• Published in: Advanced functional materials Vol. 34; no. 52
• Main Authors: Chang, Che‐Bin, Tseng, Yen‐Yang, Lu, Ying‐Rui, Yang, Yi‐Chun, Tuan, Hsing‐Yu
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.12.2024
• Subjects: Batteries; Copper; dendrite free; Deposition; Electron transport; frank‐van der merwe type growth; high entropy; High entropy alloys; Interface stability; Iron; Nanoalloys; Nanoparticles; Optical microscopy; porous structure; Potassium; potassium metal battery; Solid electrolytes; Substrates
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202411193

Potassium metal batteries (PMBs) are promising for next‐generation energy storage. However, the high reactivity of the anode causes instability in the solid electrolyte interface (SEI), resulting in Volmer‐Weber (V‐W) type deposition. To achieve uniform Frank‐van der Merwe (F‐M) type deposition, high entropy alloy nanoparticles are designed (HEA NPs) with equimolar ratios of Mn, Fe, Co, Cu, and Ni to enhance the substrate‐K metal interface. HEA NPs enhance the K affinity of the N‐doped nanocarbon fiber substrate (N‐PCNF) and maximize ion and electron transport efficiency. The dendrite‐free horizontal growth of K metal confirmed through Operando X‐ray diffraction (XRD) and optical microscopy (OM). Consequently, the asymmetric cell exhibits ultra‐long cycling stability of 2350 hours at a high current density of 8 mA cm−2. The full cell composed of molten K diffusion into HEA NPs decorated N‐PCNF anode with perylene‐3,4,9,10‐tetracarboxylic dianhydride cathode (HEA‐N‐PCNF‐K||PTCDA) delivers an energy density of 331 W h kg−1 and remains stable over 2000 cycles. This study offers a promising pathway for innovative PMBs designs with broad application prospects. The high‐entropy effect induced local charge density accumulation enhances the K affinity of the substrate, thereby reducing the critical radius for K metal nucleation. The incorporation of porous design not only diminishes local charge density but also facilitates the electron transport. The dual‐strategy enables stable Frank‐van der Merwe (F‐M) type deposition, heralding new prospects for dendrite‐free potassium metal batteries (PMBs).