Key Takeaways & Executive Findings
- •• Sodium-ion batteries exhibit superior low-temperature performance compared to lithium-ion batteries due to lower desolvation energy and diffusion barriers. • Hard carbon anodes suffer from sodium dendrite formation, low solid-phase diffusion rates, and excessive SEI formation at low temperatures. • Structural improvements, morphological design, interface optimization, and cut-off voltage adjustment are effective strategies to enhance low-temperature performance. • The sodium storage mechanism in hard carbon involves adsorption, intercalation, and filling processes, which are critical for optimizing anode design.
Abstract
Because of their excellent low-temperature (−15 to −40 °C) tolerance, sodium-ion batteries are emerging as a complement to lithium-ion batteries for use in extremely cold environments (e.g. high-latitude areas). Hard carbon has a high low-voltage sodium storage capacity and a good initial efficiency, making it one of the most promising anode materials for sodium-ion batteries. It has a complex structure, featuring closed pores, nano graphitic domains, and surface functional groups. The sodium storage sites in hard carbon are reviewed as are the widely accepted sodium storage mechanisms. The main factors contributing to the degradation of the good low-temperature performance in hard carbon anodes are considered, including sodium dendrite formation, low ion diffusion rates, and surface-side reactions. Finally, strategies to increase the low-temperature sodium storage performance of hard carbon anodes are summarized, including bulk structure design, and improvements in interfaces and cut-off voltage. Guidance is provided for improving the low-temperature performance of hard carbon anodes to accelerate the development of these batteries.
1. Introduction
In recent years, the transition from traditional fossil energy to new types of clean energy has become a global consensus. The development of energy storage technology is the key to further realizing the efficient use of renewable energy. Designing a battery with high environmental adaptability is of great significance. Lithium-ion batteries (LIBs) are widely used because of their high energy density, long cycle life, and good safety. However, with the quick development of electric vehicles and large-scale energy storage power stations, the supply-demand gap for LIBs is continuously widening, and lithium (Li) is experiencing issues with resource scarcity. At the same time, with the continuous expansion in the scope of battery application, more batteries will be applied in low temperatures, which will impose higher standards for the low-temperature performance of the battery. Therefore, the development of a new type of battery that can fill this gap is under way.
Compared with lithium, sodium (Na) is 400 times more abundant in the earth’s crust (2.75% vs. 0.0065%). It is evenly distributed and inexpensive. Similar to LIBs, sodium-ion batteries (SIBs) are also rocking chair-type batteries, where energy is stored/released by the embedding/removal of Na+ between the anode and cathode. In addition to the natural advantage of abundant Na, SIBs also have some advantages over LIBs at low temperatures[1]. The transfer of alkali metal ions in the electrolyte has a significant impact on the battery. At low temperatures, the desolvation energy of ions will increase with the reduction in mobility and the rise in electrolyte viscosity. Okoshi et al.[2] compared the desolvation energy of Li+ and Na+ in 27 organic electrolyte solvents and found that the desolvation energies of Na+ are commonly smaller by ca. 40–70 kJ mol−1. They attribute it to the weaker Lewis acidity of Na+ than Li+. Mukai et al[3]. compared the performance differences of SIB and LIB at low temperatures and discovered that SIBs have higher power and capacity retention. They attribute it to the lower diffusion potential barriers in the cathode and the relatively weak interaction between the Na+ and electrolyte. In brief, SIBs have higher reserves, low pr
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CUI Zhe, LI Bing-yu, XIONG Hang, LI Tian, XIE Ming-xin, HU Jing-ying, QIU Xia, GUI Zhu-qin, ZHOU Rui, SHI Li-luo, JU Zhi-cheng, CHEN Ya-xin (2025). A review of ways to improve the performance of hard carbon anodes in low-temperature sodium-ion batteries. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2025-6-2)
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
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Frequently Asked Questions
Why are sodium-ion batteries considered promising for low-temperature applications?
Sodium-ion batteries exhibit excellent low-temperature tolerance (−15 to −40 °C) due to lower desolvation energy of Na+ compared to Li+, weaker Lewis acidity, and lower diffusion potential barriers, resulting in higher power and capacity retention at low temperatures.
What are the main challenges for hard carbon anodes in low-temperature sodium-ion batteries?
The main challenges include sodium dendrite formation, low solid-phase diffusion rates, and excessive solid electrolyte interphase (SEI) formation, which degrade the low-temperature performance.
What strategies are proposed to improve the low-temperature performance of hard carbon anodes?
Strategies include bulk structure design (e.g., structural improvements and morphological design), interface optimization, and adjusting the cut-off voltage to mitigate issues like dendrite formation and slow diffusion.
What are the sodium storage mechanisms in hard carbon?
The sodium storage mechanisms in hard carbon include adsorption, intercalation, and filling processes, which are influenced by its complex structure with closed pores, nano graphitic domains, and surface functional groups.
How does hard carbon compare to other anode materials for sodium-ion batteries?
Hard carbon is one of the most promising anode materials due to its high low-voltage sodium storage capacity and good initial efficiency, making it suitable for low-temperature applications.
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