Mo Lulu, Chen Ai-Long, Ouyang Yue, Zong Wei, Miao Yue-E, Liu Tianxi
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China.
ACS Appl Mater Interfaces. 2021 Oct 20;13(41):48634-48642. doi: 10.1021/acsami.1c13018. Epub 2021 Oct 10.
Sodium (Na) metal is considered a promising anode material for high-energy Na batteries due to its high theoretical capacity and abundant resources. However, uncontrollable dendrite growth during the repeated Na plating/stripping process leads to the issues of low Coulombic efficiency and short circuits, impeding the practical applications of Na metal anodes. Herein, we propose a silver-modified carbon nanofiber (CNF@Ag) host with asymmetric sodiophilic features to effectively improve the deposition behavior of Na metal. Both density functional theory (DFT) calculations and experiment results demonstrate that Na metal can preferentially nucleate on the sodiophilic surface with Ag nanoparticles and uniformly deposit on the whole CNF@Ag host with a "bottom-up growth" mode, thus preventing unsafe dendrite growth at the anode/separator interface. The optimized CNF@Ag framework exhibits an excellent average Coulombic efficiency of 99.9% for 500 cycles during Na plating/stripping at 1 mA cm for 1 mAh cm. Moreover, the CNF@Ag-Na symmetric cell displays stable cycling for 500 h with a low voltage hysteresis at 2 mA cm. The CNF@Ag-Na//NaV(PO) full cell also presents a high reversible specific capacity of 102.7 mAh g for over 200 cycles at 1 C. Therefore, asymmetric sodiophilic engineering presents a facile and efficient approach for developing high-performance Na batteries with high safety and stable cycling performance.
钠（Na）金属因其高理论容量和丰富的资源，被认为是用于高能钠电池的一种有前景的负极材料。然而，在反复的钠电镀/脱镀过程中，不可控的枝晶生长会导致库仑效率低和短路问题，阻碍了钠金属负极的实际应用。在此，我们提出一种具有不对称亲钠特性的银改性碳纳米纤维（CNF@Ag）主体，以有效改善钠金属的沉积行为。密度泛函理论（DFT）计算和实验结果均表明，钠金属能够优先在含有银纳米颗粒的亲钠表面成核，并以“自下而上生长”模式均匀地沉积在整个CNF@Ag主体上，从而防止在阳极/隔膜界面处出现不安全的枝晶生长。优化后的CNF@Ag框架在1 mA cm²下进行1 mAh cm²的钠电镀/脱镀过程中，500次循环的平均库仑效率高达99.9%。此外，CNF@Ag-Na对称电池在2 mA cm²下可稳定循环500小时，且电压滞后较低。CNF@Ag-Na//NaV(PO₄)全电池在1 C下超过200次循环时，也呈现出102.7 mAh g的高可逆比容量。因此，不对称亲钠工程为开发具有高安全性和稳定循环性能的高性能钠电池提供了一种简便而有效的方法。
