Supplementary information files for The Pseudocapacitive Nature of CoFe2O4 Thin Films

Supplementary information files for The Pseudocapacitive Nature of CoFe2O4 Thin Films.Nanostructured Cobalt ferrite (CoFe₂O₄) thin films are fabricated by aerosol-assisted chemical vapour deposition (AACVD) and studied for application in supercapacitors. XRD and Raman spectroscopic analysis confirms the formation of single phase CoFe₂O₄. SEM analysis shows that the thin film morphology consists of nanoparticles less than 100 nm in size that are sintered together to form larger dendrites raised from the substrate. The larger dendrites range from 0.5–1 μm in diameter and are uniformly distributed over the FTO substrate, providing a highly porous structure which is desired for supercapacitor electrodes. Three-electrode electrochemical measurements reveal that CoFe₂O₄ is pseudocapacitive and is highly conducting. Studies of CoFe₂O₄ thin films in two-electrode symmetric supercapacitor configuration show a capacitance of 540 μF cm⁻² and a relaxation time constant of 174 ms. Around 80% of the capacitance is retained after 7000 charge-discharge cycles when a maximum charging voltage of 1 V was used, indicating that the pseudocapacitive processes in CoFe₂O₄ are highly reversible and that it exhibits excellent chemical stability in 1 M NaOH alkaline electrolyte solution. The results show that CoFe₂O₄ is a cheap and promising alternative pseudocapacitive material to replace the expensive pseudocapacitive materials.<br>

《CoFe₂O₄薄膜的赝电容特性》补充信息文件。纳米结构钴铁氧体（CoFe₂O₄）薄膜通过气溶胶辅助化学气相沉积（AACVD）制备，并针对超级电容器应用展开研究。X射线衍射（XRD）和拉曼光谱分析证实了单相CoFe₂O₄的形成。扫描电子显微镜（SEM）分析显示，薄膜形貌由尺寸小于100 nm的纳米颗粒构成，这些颗粒烧结形成从基底凸起的较大枝晶。较大枝晶的直径范围为0.5–1 μm，在FTO基底上均匀分布，形成超级电容器电极所需的高孔隙结构。三电极电化学测试表明，CoFe₂O₄具有赝电容特性且导电性优异。在双电极对称超级电容器构型中对CoFe₂O₄薄膜的研究显示，其电容为540 μF cm⁻²，弛豫时间常数为174 ms。当使用1 V的最大充电电压时，经过7000次充放电循环后仍保留约80%的电容，表明CoFe₂O₄中的赝电容过程具有高度可逆性，且在1 M NaOH碱性电解质溶液中表现出优异的化学稳定性。研究结果表明，CoFe₂O₄是一种廉价且具有前景的替代赝电容材料，可取代昂贵的赝电容材料。