Lithium Dependent Electrochemistry of p‐Type Nanocrystalline CuCrO 2 Films
Lithium Dependent Electrochemistry of p‐Type Nanocrystalline CuCrO 2 Films
复制标题
p型纳米晶CuCrO 2 薄膜的锂依赖性电化学
DOI：
10.1002/celc.202200825
复制
发表时间：
2022
期刊：
影响因子：
4
通讯作者：
Farnum, Byron H.
中科院分区：
文献类型：
--
作者：
Chown, Amanda L.;Yeasmin, Humaira;Paudel, Rajendra;Comes, Ryan B.;Farnum, Byron H.
合成了CuCrO 2纳米晶并将其制备成介孔薄膜，研究了其电化学性能，发现其具有很强的[Li+]依赖性.随着电解质中[Li+]的增加，除了在E1/2=−0.43 V vs Fc+/0处生长新的氧化还原特征外，还观察到Cu 2 +/+氧化还原电位的阳极偏移。 这一新的特征归因于Cu 2 +/+氧化还原化学伴随着Li+占据铜空位表面缺陷。Li+占据的平衡常数和最大电荷分别为K=0.057 M− 1和15.5 mC。 最大电荷接近基于铜空位的测量浓度的11 mC的预期值。 明显的Li+依赖性电化学表明CuCrO 2的行为与锂离子电池中的阴极相似。因此，计时电位法实验揭示了在第2次循环时的7.8 mA h g-1充电容量和在10次循环中从83%增加到91%的循环效率。 然而，随着循环次数的增加，观察到充电容量显著降低，这归因于锂偶联电化学的损失。这些研究增加了我们对p型氧化物中表面缺陷及其对太阳能电池器件中空穴复合的影响的理解。
CuCrO2nanocrystals were synthesized and fabricated into mesoporous thin films to study their electrochemical properties, where a strong [Li+] dependence was observed. An anodic shift in the Cu2+/+redox potential was observed with increased [Li+] in the electrolyte, in addition to the growth of a new redox feature at E1/2=−0.43 V vs Fc+/0. This new feature was attributed to Cu2+/+redox chemistry accompanied by Li+occupation in copper vacancy surface defects. The equilibrium constant and maximum charge for Li+occupation were determined to be K=0.057 M−1and 15.5 mC, respectively. The maximum charge was close to the expected value of 11 mC based on the measured concentration of copper vacancies. The pronounced Li+dependent electrochemistry suggests that CuCrO2behaves similarly to cathodes in Li‐ion batteries. Thus, chronopotentiometry experiments revealed a 7.8 mA h g−1charge capacity at cycle 2 and increasing cycling efficiency from 83 to 91 % over 10 cycles. However, a pronounced decrease in charge capacity was observed with increased cycles, attributed to a loss in lithium‐coupled electrochemistry. These studies add to our understanding of surface defects in p‐type oxides and their effect on hole recombination in solar cell devices.