Supercharging Batteries With Improved Material Design

A study led by myself, Assistant Prof. Edison Huixiang Ang from the National Institute of Education/Nanyang Technological University Singapore, with Prof. Xing-Long Wu and Dr. Jin-Zhi Guo from Northeast Normal University, has advanced sodium–ion battery technology. By enhancing cathodes with a vanadium–iron phosphate structure, we achieved superior ion conductivity and stability using cost-effective, eco-friendly materials. Published in Advanced Science under the 2023 Rising Stars special collection, this breakthrough could revolutionize large-scale energy storage.

Fueling tomorrow: Innovating sodium–ion batteries for sustainable energy

Driven by the need for cost-effective and eco-friendly energy storage solutions, our team embarked on a mission to enhance sodium–ion battery technology. With a focus on improving cathode performance, our research aimed to address the growing demand for efficient energy storage in a rapidly evolving world. To address the high cost, toxicity, poor conductivity, structural instability and limited cycling performance of conventional sodium (Na) super ionic conductor (NASICON) materials, our team developed Na₃.₀₅V₁.₀₃Fe₀.₉₇(PO₄)₃ (NVFP) encircled by highly conductive Ketjen Black (KB). We aimed to achieve enhanced ion diffusion, reduced volume change and superior cycling stability, paving the way for more sustainable and accessible energy solutions, aligning with global efforts towards a greener future.

Powering progress: Unveiling breakthroughs in sodium–ion battery technology

The team synthesized NVFP with KB via a ball-milling assisted sol-gel method. We examined the structure modulation using in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy during electrochemical progress.

The key findings of the paper were that:

• Incorporating iron into vanadium-based cathodes enhanced conductivity and stability.
• Pearl-like KB branch chains encircling NVFP particles improved overall conductivity.
• An enhanced ion diffusion ability and low volume change (2.99%) were observed in the modified cathodes.
• Remarkable cycling performance was achieved: 87.7% capacity retention over 5000 cycles at 5 C.
• Full cells exhibited a capacity of 84.9 mAh g⁻¹ at 20 C with minimal capacity decay (0.016% per cycle at 2 C).

Empowering energy: Advancing sustainable battery solutions

We attribute the enhanced performance of the modified cathodes to a combination of factors. By incorporating iron into the vanadium-based structure and introducing the unique morphology of the KB branch chains, they created a synergistic effect that significantly improved conductivity and stability. This novel approach addresses critical challenges, including reducing the cost and toxicity of vanadium, enhancing ionic and electronic conductivity, improving structural stability, achieving durable cycling performance and maintaining high energy density and rate capability in the sodium–ion battery technology, laying the groundwork for practical applications in energy storage systems. This novel approach is environmentally friendly compared to alternative approaches because it reduces the use of toxic and expensive vanadium by incorporating cheaper, earth-abundant iron, and enhances battery performance and stability without relying on hazardous materials.

These findings represent a significant advancement in the field of energy storage. By offering a cost-effective and environmentally-friendly solution for large-scale battery production, this innovation has the potential to revolutionize various industries. From renewable energy storage to electric vehicles, the adoption of sodium–ion batteries could be accelerated, leading to a more sustainable future.

While the study showcases impressive performance enhancements, it primarily focuses on laboratory-scale experiments. Scaling up production and overcoming challenges in large-scale manufacturing remain significant hurdles. Furthermore, the long-term stability and performance of the modified cathodes in real-world applications necessitate further investigation. Recognizing these limitations underscores the importance of ongoing research and development to realize the potential of this technology fully in practical settings.

Pioneering progress: Charting the path forward

We propose several avenues for future exploration. Firstly, we suggest scaling up production processes to evaluate the feasibility of large-scale manufacturing. Additionally, investigating the long-term stability and performance of the modified cathodes in practical applications is crucial. Further experiments could focus on optimizing the composition and morphology of the cathode materials to enhance performance and address the remaining challenges. Continual refinement of this technology will be essential for its successful integration into sustainable energy storage systems on a commercial scale.

Reference: Zhao XX, Fu W, Gou JZ, Wu XL, Ang EH, et al. Pearl-structure-enhanced NASICON cathode towards ultrastable sodium–ion batteries. Adv. Sci. 2023;10(19): 2301308. doi:10.1002/advs.202301308

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