Liquid metal induced self-diffusion growth model for long-cycling potassium metal batteries
image: Liquid metal alloying collector (LM@Cu) was constructed by a simple one-step brush-coating method and induced self-diffusive planar deposition behavior of K metal, which effectively suppressed the generation of K dendrites on the electrodes during the cycling process.
Credit: Nano Research, Tsinghua University Press
In recent years, potassium metal batteries (PMBs) and potassium-ion batteries (PIBs) have garnered significant attention due to their unique advantages. Potassium, an alkali metal with crustal abundance approximately a thousand times greater than lithium, shares similar chemical properties but exhibits a lower standard redox potential compared to sodium, magnesium, and other metals, enabling higher output voltages. Additionally, the weak Lewis acidity and low desolvation energy of potassium ions contribute to enhanced ion mobility and conductivity, thereby improving battery diffusion kinetics. Despite the promise of potassium metal anodes—owing to their high theoretical capacity (687 mAh g-1) and lowest redox potential—their practical application faces critical challenges: the fragile solid electrolyte interphase (SEI) formed by reactive potassium metal and electrolytes tends to fracture, leading to dendrite growth and active potassium loss, which severely degrade Coulombic efficiency and cycling stability.
The research team published their findings in Nano Research on July 8, 2025.
The key to regulating potassium deposition behavior lies in reducing nucleation overpotential and inducing uniform growth. Current strategies, such as constructing potassiophilic substrates (e.g., Cu3Pt alloys, amine-functionalized carbon cloth), aim to improve interfacial affinity. However, these methods suffer from complex preparation processes and insufficient theoretical analysis of deposition models.
This study proposes a simple liquid alloy (GaInSn) coating strategy to fabricate a potassiophilic LM@Cu substrate. The superior electrolyte wettability and high potassium adsorption energy (confirmed by DFT calculations) of LM@Cu promote uniform K+ distribution, guiding potassium to deposit via a self-diffusive planar growth mode. In situ optical microscopy and ex situ electron microscopy analyses further reveal its mechanism in suppressing dendrites and mitigating volume expansion. The LMK composite anode, constructed by pre-depositing potassium on LM@Cu, demonstrates an initial Coulombic efficiency of up to 99.86 % and retains a reversible capacity of 78.2 mAh g-1 after 4900 cycles at 500 mA g-1 when paired with a PTCDI cathode. This liquid metal interface engineering offers a novel approach to developing long-cycle-life potassium metal batteries.
Other contributors include Shuanghong Xia, Hao Zou, Bo Huang, Ling Li and Song Chen from Province-Ministry Co-construction Collaborative Innovation Center of Hebei Photovoltaic Technology, College of Physics Science and Technology, Hebei University, Baoding 071002, China.
We gratefully acknowledge the financial support from the following sources: the National Natural Science Foundation of China (NSFC) (grants 52171206, 52271209), the Key Project of Hebei Natural Science Foundation (F2024201031, E2020201030), the Science Research Project of Hebei Education Department (JCZX2025019), the Interdisciplinary Research Program of Hebei University (DXK202401).
About the Author
Wenming Zhang, Professor and Ph.D. Supervisor at Hebei University, is a recipient of the Hebei Provincial Outstanding Youth Fund, Hebei Youth Top Talent, Hebei University Outstanding Kunyu Scholar, and Guest Professor at Hainan University. His research focuses on advanced materials and energy devices. He has led 3 NSFC projects and over 10 provincial/ministerial initiatives. He has published about 100 high-impact papers as first/corresponding author in journals including Adv. Mater., Mater. Today, Energy Storage Mater., Nano Lett., and Nano Energy. His work is widely cited, and he holds multiple patents. He authored one national textbook and co-authored three, and was recognized as a "Provincial Excellent Instructor" for mentoring award-winning student teams. Besides, he received the 2022 Hebei Natural Science Third Prize and was listed among the World's Top 2% Scientists in 2023.
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.