In this study, we developed a facile chemical precipitation approach for the synthesis of heterogeneous Co₃O₄ nanosphere/Co(OH)₂ nanosheet hybrids in the presence of polyvinylpyrrolidone (PVP) as a phase-controlling reagent. The crystalline phase and morphology of the product varied upon changing the chain length of PVP (from 8k to 120k), with short-chain PVP favoring the formation of Co₃O₄ nanospheres and long-chain PVP favoring the synthesis of Co(OH)₂ nanosheets. Accordingly, heterogeneous Co₃O₄/Co(OH)₂ hybrids of various blending ratios were readily prepared in the presence of PVP of different molecular weights. The molecular weight of PVP also affected the electrochemical properties of the Co₃O₄ nanosphere/Co(OH)₂ nanosheet composites. When using PVP of moderate chain length (58k), the resultant Co₃O₄/Co(OH)₂ composite exhibited the optimal supercapacitive performance, characterized by an excellent specific capacitance of 771.2 F g⁻¹ at 1 A g⁻¹, and retained approximately 68.5% of this capacitance when operated at a high current density of 10 A g⁻¹. Furthermore, this composite displayed an excellent charge/discharge cycling life at a current density of 4 A g⁻¹, with a capacitance retention of 93.3% after 3000 repeated cycles.

在这项研究中，我们开发了一种简便的化学沉淀方法，用于在聚乙烯吡咯烷酮（PVP）作为相控制剂的情况下合成异质Co ₃ O ₄纳米球/ Co（OH）₂纳米片杂化物。产物的结晶相和形态随PVP链长的变化（从8k变为120k）而变化，短链PVP有利于Co ₃ O ₄纳米球的形成，长链PVP有利于Co（OH）的合成₂纳米片。因此，异质Co ₃ O ₄ / Co（OH）₂在不同分子量的PVP存在下，可以很容易地制备出各种混合比例的杂化物。PVP的分子量也影响Co ₃ O ₄纳米球/ Co（OH）₂纳米片复合材料的电化学性能。当使用中等链长（58k）的PVP时，所得的Co ₃ O ₄ / Co（OH）₂复合材料表现出最佳的超电容性能，其特征在于在1 A g ^-1下具有771.2 F g ^-1的优异比电容，并且在10 A g ^-1的高电流密度下工作时，仍可保留约68.5％的电容。此外，该复合材料在4 A g ^-1的电流密度下表现出优异的充电/放电循环寿命，在3000次重复循环后的电容保持率为93.3％。