香港科技大学的研究人员开发出一种新材料，可能解决锂金属电池面临的最大难题之一。
该团队创建了一种单晶3D硼酸盐共价有机框架，作为固态电解质使用，同时提高了安全性和性能。锂金属电池被视为继当前锂离子系统之后的下一步，特别是在电动汽车和大规模储能领域。然而，由于锂枝晶的形成和界面不稳定导致的退化和短路问题，它们一直面临安全性挑战。
由于其多孔且稳定的结构，共价有机框架（COF）一直被探索作为潜在的电解质材料。然而，现有的大多数版本是多晶的，这会在晶界处产生电阻，限制了离子通过材料的效率。为了克服这一问题，团队使用COF-303作为模板，构建了具有高度有序离子通道的单晶结构。
这种设计减少了晶间电阻并实现了更均匀的锂沉积，有助于抑制枝晶生长。材料有序的离子路径还允许更一致的离子流穿过电解质，减少了热点和不均匀反应。这有助于在实际使用条件下延长电池寿命，因为重复充电循环通常会导致性能损失和安全风险。
突破枝晶生长障碍
新材料在多个关键指标上表现出强劲的电化学性能。它在室温下实现了8.1 mS/cm的离子电导率，锂离子迁移数为0.98，允许电池内快速且具有选择性的离子传输。
该系统还显示出更高的稳定性。测试证明，在对称电池中实现了超过2000小时的稳定锂沉积和剥离，表明了长期的运行可靠性和更低的安全风险。
Researchers at Hong Kong University of Science and Technology have developed a new material that could solve one of the biggest problems in lithium metal batteries.
The team has created a single-crystalline 3D borate covalent organic framework that works as a solid-state electrolyte, improving both safety and performance.
Lithium metal batteries are seen as the next step beyond current lithium-ion systems, especially for electric vehicles and large-scale energy storage.
But they have struggled with safety issues, mainly due to the formation of lithium dendrites and unstable interfaces that lead to degradation and short circuits.
Covalent organic frameworks have been explored as potential electrolyte materials because of their porous and stable structures.
However, most existing versions are polycrystalline, which creates resistance at grain boundaries and limits how efficiently ions can move through the material.
To overcome this, the team used COF-303 as a template to build a single-crystalline structure with highly ordered ion channels.
This design reduces intergrain resistance and enables more uniform lithium deposition, helping suppress dendrite formation.
The material’s ordered ion pathways also allow more consistent ion flow across the electrolyte, reducing hotspots and uneven reactions. This could help improve battery lifespan under real-world conditions, where repeated charging cycles often lead to performance loss and safety risks.
Breaking dendrite growth barrier
The new material delivers strong electrochemical performance across several key metrics. It achieves an ionic conductivity of 8.1 mS cm−1 at room temperature and a Li+ transference number of 0.98, allowing fast and selective ion transport within the battery.
The system also shows improved stability. Tests demonstrated stable lithium deposition and stripping for more than 2,000 hours in symmetric cells, indicating long-term operational reliability and reduced safety risks.
In full-cell configurations using LiFePO4 cathodes, the batteries maintained 91.8 percent capacity retention over 600 cycles, with a Coulombic efficiency of 99.98 percent.
The cells delivered an initial capacity of 147 mAh g−1, pointing to consistent performance over extended use.
The work highlights how structural control at the material level can directly impact battery performance.
By eliminating the disorder seen in polycrystalline frameworks, the researchers were able to improve both efficiency and safety in lithium metal systems.
Toward safer energy storage
“Our research highlights the promising viability of single-crystalline 3D B-COFs as quasi-solid-state electrolytes,” said Prof. Yoonseob Kim.
“By eliminating the structural disorders found in polycrystalline materials, we have taken a significant step toward realizing high-performance, safe energy storage solutions that are crucial for a greener future.”
The research was conducted in collaboration with Shanghai Jiao Tong University, reflecting growing
