碳基负极材料具有成本低、来源广、电导率高、形态易控制等特点，被广泛应用于各种电池储能系统中。然而，目前市售的作为锂/钠离子电池活性材料的负极材料普遍存在体积变化大、倍率性能差的问题。
近日，青岛科技大学刘治明教授、李慧芳教授和王朋副教授等人在Science China Materials发表研究论文，根据希夫碱反应原理，通过简单的水热、碳化和刻蚀工艺，合成了由二维纳米片组装而成的N、S共掺杂多孔碳微球（N、S-PCS），在锂离子电池和钠离子电池中都表现出优异的电化学性能。
本文要点
1) N、S-PCS结构是通过从碳骨架中去除Fe7S8纳米颗粒，形成掺杂N、S的多孔微球。因此，通过杂原子掺杂和表面工程，碳材料的微观形貌特征、孔隙结构和导电性能得到了有效优化。2) 制备的N、S-PCS电极在锂离子电池和钠离子电池中都表现出优异的电化学性能。对于锂离子电池，在0.1和20 A g−1的条件下，其可逆容量分别达到1045和237 mAh g−1；对于钠离子电池，它显示出良好的循环稳定性，在1 A g−1的条件下循环500次后，容量为157 mAh g−1。3) 实验和理论计算结果证实，N、S共掺杂策略有助于提高负极材料结构稳定性、缩短离子扩散路径和促进反应动力学，从而实现其优异的电化学性能。这项工作对金属离子电池非金属掺杂功能化多孔碳结构的实际应用具有指导意义。Figure 1. The synthesis scheme of N, S-PCS.Figure 2. (a, b) SEM images of N, S-PCS. (c) HAADF-STEM image of N, S-PCS. (d, e) The fragment TEM images of N, S-PCS. (f) The fragment HRTEM image of N, S-PCS. (g) Element mapping images of N, S-PCS.Figure 3. The electrochemical performance of N, S-PCS in LIBs. (a) CV curves of N, S-PCS for the first five cycles at a scan rate of 0.1 mV s−1. (b) Voltage profile of N, S-PCS in LIBs at 0.1 A g−1 current density for the 2nd–5th cycles. (c) Rate performance of N, S-PCS at various current densities from 0.1 to 20 A g−1. Cycling performance of N, S-PCS at the current densities of (d) 0.5 and (e) 5 A g−1, respectively.Figure 4. The first-principles calculations. (a–c) Models, and (d–f) charge density differences of the pristine 2D carbon nanosheets, N, S co-doped 2D carbon nanosheets and N, S co-doped 2D carbon nanosheets with defects, respectively. (g–i) Corresponding PDOS (The dashed line at 0 eV indicates the Fermi level).Yutian Chen, Jie You, Xiaoran Zhao, Mai Li, Xiaolei Han, Hui Liu, Hongran Sun, Xiaojun Wang, Huifang Li, Peng Wang, Zhiming Liu. Porous carbon microspheres assembled by defective nitrogen and sulfur co-doped nanosheets as anode materials for lithium-/sodium-ion batteries. Sci. China Mater. (2024).https://doi.org/10.1007/s40843-024-3041-3
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