CsPbBr$_{3-x}$I$_x$纳米晶电极中的钠掺入：晶格收缩与场驱动碘析出的抑制
Sodium Incorporation in CsPbBr$_{3-x}$I$_x$ Nanocrystal Electrodes: Lattice Contraction and the Suppression of Field-Driven Iodine Expulsion
- Indian Institute of Technology Roorkee（印度理工学院鲁尔基分校）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
本研究通过钠掺杂使CsPbBr$_{3-x}$I$_x$纳米晶电极晶格收缩，抑制场驱动碘析出，将循环稳定性从崩溃提升至2500次循环保留97%电容。
中文摘要 AI 辅助
混合卤化物钙钛矿纳米晶电极在超级电容器中因场驱动卤化物偏析而失效。在未掺杂的$\mathrm{CsPbBr_2I}$中，这表现为电容在第1378次循环时攀升至首次循环值的218%，随后在第2500次循环时崩溃至39%，且循环电极的碘信号完全消失。本研究测试钠掺入是否能抑制该失效模式。通过配体辅助再沉淀法，以Na/Pb前驱体比例1.25:1.00制备了Na掺杂的$\mathrm{CsPbBr_{3-x}I_x}$（$x = 0, 1, 2$）纳米晶，并与未掺杂的对应物在0.1 M四丁基四氟硼酸铵的无水二氯甲烷溶液中进行比较。钠使$\mathrm{CsPbBr_3}$的赝立方晶格参数在校正试样位移后从$5.908 \pm 0.029$ $\mathring{\mathrm{A}}$收缩至$5.851 \pm 0.019$ $\mathring{\mathrm{A}}$。在0.3 A g$^{-1}$下，每种组分的比电容均上升，分别从42升至75、从63升至96、从56升至84.5 F g$^{-1}$。Na-$\mathrm{CsPbBr_2I}$在175 $\Omega$时具有最低的电荷转移电阻，在$1.6 \times 10^{-16}$ m$^2$ s$^{-1}$时具有最高的离子扩散系数，且在所有考察电位下，幂律指数介于0.33和0.45之间，表明电荷存储受限于通过孔网络的离子传输，而非界面过程。在含钠的（Na-$\mathrm{CsPbBr_2I}$）电极中，电容上升在第600次循环时仅达到115%，随后没有崩溃，在第2500次循环时保留了97%，超出首次循环值的部分减少了7.9倍。碘以不变的结合能保留，元素映射测得的Br:I比在循环后为2.30，而循环前为2.25。
英文摘要
Mixed-halide perovskite nanocrystal electrodes fail in supercapacitors through field-driven halide segregation. In undoped $\mathrm{CsPbBr_2I}$, this appears as a capacitance that climbs to 218% of its first-cycle value by cycle 1378 and then collapses to 39% by cycle 2500, with complete loss of the iodine signal from the cycled electrode. This work tests whether sodium incorporation suppresses that failure mode. Na-doped $\mathrm{CsPbBr_{3-x}I_x}$ ($x = 0, 1, 2$) nanocrystals were prepared by ligand-assisted reprecipitation at a Na/Pb precursor ratio of 1.25:1.00 and compared with undoped analogues in 0.1 M tetrabutylammonium tetrafluoroborate in anhydrous dichloromethane. Sodium contracts the pseudocubic lattice parameter of $\mathrm{CsPbBr_3}$ from $5.908 \pm 0.029$ to $5.851 \pm 0.019$ $\mathring{\mathrm{A}}$ after correction for specimen displacement. Specific capacitance at 0.3 A g$^{-1}$ rises for every composition, from 42 to 75, from 63 to 96, and from 56 to 84.5 F g$^{-1}$. Na-$\mathrm{CsPbBr_2I}$ gives the lowest charge-transfer resistance at 175 $Ω$ and the highest ion diffusion coefficient at $1.6 \times 10^{-16}$ m$^2$ s$^{-1}$, and power-law exponents between 0.33 and 0.45 at all potentials examined show that charge storage is limited by ion transport through the pore network rather than by the interfacial process. In the sodium-containing (Na-$\mathrm{CsPbBr_2I}$) electrode, the capacitance rise reaches only 115% at cycle 600, no collapse follows, and 97% is retained at 2500 cycles, the excess above the first-cycle value being reduced by a factor of 7.9. Iodine is retained at unchanged binding energy, and the Br:I ratio measured by elemental mapping is 2.30 after cycling against 2.25 before.
