Bottom-Up Growth Strategy for High-Areal-Capacity Rechargeable Al Batteries (Nano Energy, Prof. Du's Group, XJTU)
Date: June 26, 2023 Source:
In recent years, the global energy system has been shifting from fossil fuels to renewable energy, and energy storage is critical for the utilization of renewable energy. Energy storage can be realized in multiple ways, and batteries, which store energy electrochemically, represent one of the most efficient and scalable options. Aluminum-ion batteries (AIBs) have attracted extensive attention owing to their low cost, high theoretical capacity (theoretical volumetric and gravimetric capacities of 8048 mAh·cm⁻³ and 2981 mAh·g⁻¹, respectively), and high safety (non-flammable upon exposure to water and air). Nevertheless, dendrite growth is inevitable for metal-anode batteries during charging due to uncontrolled surface morphology, chemical reactions and hydrodynamic processes. Recent studies have demonstrated that 3D metal anodes can enlarge the effective contact area between the electrode and electrolyte and reduce the local current density, thereby mitigating corrosion and dendrite formation on the electrode surface. However, metal particles still tend to preferentially deposit on the top region of the electrode because of the high electric field strength and short ion diffusion pathway. For aluminum battery systems with high areal capacity, the amount of deposited aluminum per unit area inevitably increases. Excessive aluminum deposits may bridge the cathode and anode and accelerate dendrite propagation, severely compromising the long-term stability and safety of the battery.
To address this challenge, the research team led by Prof. Xianfeng Du from the School of Chemistry, Xi’an Jiaotong University, proposed an aluminum battery anode architecture with a bottom-growth configuration (2P-Al₂O₃/Al anode), which generates a reversed electric field distribution (E<sub>bottom</sub> > E<sub>top</sub>) to guide the directional deposition of Al. A stable electrode–electrolyte interface can be maintained even under high-areal-capacity conditions. Compared with conventional planar Al anodes, the 2P-Al₂O₃/Al anode offers the following key advantages: (1) The 2P-Al₂O₃/Al anode redistributes the electric field over the electrode and induces preferential Al deposition at the bottom, increasing the safety gap between the separator and the deposits; (2) The large specific surface area provides abundant nucleation sites for Al and helps lower the nucleation overpotential; (3) The 3D electrode structure alleviates electrode expansion during Al deposition. The 2P-Al₂O₃/Al anode delivers a more stable electrode–electrolyte interface and longer cycling lifespan. Even at a high areal capacity of 5 mAh·cm⁻², it can operate continuously for more than 1200 hours, over six times the duration achieved by planar Al anodes. This strategy is practically meaningful for assembling aluminum batteries with high energy density and superior cycling stability.
Recently, this work was published in the top international journal Nano Energy (Impact Factor: 19.1) under the title Bottom Growth Strategy for High Areal Capacity Rechargeable Aluminum Batteries. The first author is Ph.D. candidate Shixin Wang from the School of Chemistry, Xi’an Jiaotong University. Corresponding authors are Prof. Xianfeng Du and Associate Prof. Lilong Xiong from the School of Chemistry, Xi’an Jiaotong University. Xi’an Jiaotong University is the sole corresponding institution. This represents another research achievement from Prof. Xianfeng Du’s group in the field of aluminum batteries. The study was supported by the National Natural Science Foundation of China and the Key Program of the Natural Science Foundation of Shaanxi Province.
Prof. Xianfeng Du from the School of Chemistry has long devoted himself to research on electrode materials, dielectrics, electrolytes, solid-state engineering, flexible design and integrated devices for electrolytic capacitors, Li(Na)-ion batteries, aluminum-ion batteries, supercapacitors and flexible wearable sensors. To date, he has published more than 60 research papers in renowned international journals and conference proceedings including Adv. Funct. Mater., Energy Storage Mater., J. Mater. Chem. A, Carbon, ACS Appl. Mater. Inter., Adv. Mater., Inorg. Chem. Front. and J. Am. Ceram. Soc., and filed nearly 50 invention patents.
Article link:https://www.sciencedirect.com/science/article/pii/S2211285523004639
Homepage of Prof. Xianfeng Du's Research Group:http://gr.xjtu.edu.cn/web/xianfengdu