As global demand for renewable energy systems, electric vehicles, and high-capacity energy storage continues to rise, various battery chemistries have been under investigation. In recent years, lithium-ion (Li-ion) batteries have received considerable attention owing to their unique properties. However, the restrictions of lithium resources and the intrinsic energy-density constraints of Li-ion technology have intensified the search for alternative battery types for guaranteeing long-term energy security and sustainability.
Calcium-ion batteries (CIB) have attracted unprecedented attention in the battery industry. This is because calcium is abundant, inexpensive, and operates within an electrochemical window comparable to that of lithium. Despite the advantages, practical development of CIBs has been limited by slow calcium-ion mobility and insufficient stability during repeated charge-discharge cycles; hence the direct competition of the calcium-based systems with commercial Li-ion batteries has been prevented.
To overcome such challenges, a novel approach was reported by Associate Professor Yoonseob Kim’s research group at the Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology. The study, published in Advanced Science, titled “High-Performance Quasi-Solid-State Calcium-Ion Batteries from Redox-Active Covalent Organic Framework Electrolytes”, introduces a novel CIB design based on redox covalent organic frameworks, that function as quasi-solid-state electrolytes (QSSEs). The integration of laboratory experiments with computational simulations demonstrated that not only these ordered nano-channels enhance ion transport capability (>0.53), but they also contribute to improving ionic conductivity (0.46 mS.cm–1) under ambient conditions, and structural stability of the battery during long-term operation.
Using this approach, the team successfully constructed a complete CIB cell. The prototype delivered a reversible specific capacity of 155.9 mAh.g⁻¹ at a current density of 0.15 A.g⁻¹. Even under a higher current density of 1 A g⁻¹, the battery maintained more than 74.6% of its original capacity after 1,000 charge-discharge cycles, indicating excellent durability and cycling performance.
According to the researchers, these results demonstrate that redox-active covalent organic framework electrolytes can significantly enhance the practicality of CIBs. The study highlights the strong potential of CIBs as an environmentally friendly alternative to lithium-based systems and represents an important step toward next-generation energy storage technologies suitable for clean energy infrastructures and future electric mobility.
Reference: “High-Performance Quasi-Solid-State Calcium-Ion Batteries from Redox-Active Covalent Organic Framework Electrolytes” by Zhuoyu Yin, Jixin Wu, Ye Tian, Yufei Yuan, Muhua Gu, Lei Cheng, Yanming Wang and Yoonseob Kim, 16 November 2025, Advanced Science.
DOI: 10.1002/advs.202512328
The project was conducted in collaboration with researchers at Shanghai Jiao Tong University.
Date: February 16-2026
Source: https://scitechdaily.com/breakthrough-calcium-ion-battery-could-challenge-lithium-for-clean-energy/
Website: www.nanoscietec.com
