As demand for safe and low-cost energy storage grows, aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates. However, their practical application is hindered by cathode instability and poor low-temperature performance. Now, researchers from The Hong Kong Polytechnic University and Shenzhen University, led by Professor Zijian Li, have developed a novel K⁺ and CN co-intercalated NHVO (KNVO-CN) cathode that delivers exceptional performance across a wide temperature range.
Why K⁺/CN Co-Intercalation Matters
* Enhanced Reaction Kinetics: The synergistic effect of K⁺ and CN reduces electrostatic interactions and lowers the Zn diffusion barrier.
* Structural Stability: Expanded interlayer spacing (10.62 Å) and increased oxygen vacancies improve structural integrity during cycling.
* Wide-Temperature Operation: Delivers 111.3 mAh g at -20 °C and 208.6 mAh g at 60 °C, even at 20 A g.
* Long-Term Durability: Retains 174.2 mAh g after 10,000 cycles at 20 A g, with 78.2% capacity retention at 10 A g over 5,000 cycles.
Innovative Design and Features
* Tunable Interlayer Spacing: Adjusting CN content optimizes ion transport and mechanical flexibility.
* Synergistic Intercalation: K⁺ boosts capacity; CN enhances stability -- together they outperform single-intercalation strategies.
* Reversible Phase Transitions: Ex situ XRD, Raman, and XPS confirm reversible Zn and HO co-intercalation without structural collapse.
* Pouch Cell Viability: Demonstrates stable performance under bending (0-180°) and powers commercial devices like thermometers.
Applications and Future Outlook
* Extreme Environment Energy Storage: Ideal for cold-climate electronics, wearable devices, and grid storage.
* Scalable Synthesis: Uses low-cost hydrothermal and stirring methods, suitable for mass production.
* Next-Gen Cathode Design: Offers a blueprint for co-intercalation strategies in layered vanadates and beyond.
* Challenges and Opportunities: Future work will explore other co-intercalants and optimize electrolytes for even wider temperature ranges.
This work provides a practical and scalable pathway to high-performance, wide-temperature AZIBs. It underscores the power of synergistic material engineering in overcoming long-standing cathode limitations. Stay tuned for more innovations from Professor Zijian Li and his team!