Hefei National Laboratory for Physical Sciences at the Microscale, Department of Applied Chemistry, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, 230026, China.
School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, 230009, China.
Small. 2022 May;18(18):e2107199. doi: 10.1002/smll.202107199. Epub 2022 Apr 3.
Na metal anode (NMA) is one of the most promising candidate materials for next-generation low-cost sodium metal batteries. However, the preferred deposition of Na metal at the anode/separator interface increases the risk of dendrite penetration of the separator, consequently, reduces safety and life of batteries with NMA. In this study, a Na deposition-regulating strategy is shown by designing a gradiently graphitized 3D carbon fiber (CF) framework as host (grad-CF), whereby Na is guided to deposit preferentially at the bottom of the anode, safely away from the separator. The obtained Na anode significantly reduces the probability of dendrite-induced short circuits. The grad-CF host enables NMA stable cycling at a high current density of 6 mA cm . When the Na@grad-CF is applied as anode in full cells pared with Na V (PO ) (NVP) cathode, it exhibits a reversible capacity of 73 mA h g after 500 cycles with a low decay rate of 0.13%.
金属钠电极（NMA）是下一代低成本钠金属电池最有前途的候选材料之一。然而，钠金属在阳极/隔膜界面的优先沉积增加了隔膜枝晶穿透的风险，从而降低了具有 NMA 的电池的安全性和寿命。在这项研究中，通过设计梯度石墨化 3D 碳纤维（CF）框架作为主体（grad-CF），显示了一种钠沉积调节策略，从而引导钠优先在阳极底部沉积，远离隔膜，从而安全地沉积。所得到的钠阳极显著降低了枝晶诱导短路的概率。grad-CF 主体使 NMA 能够在 6 mA cm 的高电流密度下稳定循环。当 Na@grad-CF 用作与 NaV(PO)（NVP）阴极配对的全电池的阳极时，在 500 次循环后具有 73 mA h g 的可逆容量，衰减率低至 0.13%。
