Synthesis Of Nickel Cobalt Oxides As Electrode Materials For Flexible Supercapacitors

Nowadays,human’s demand for smart and convenient wearable devices is increasing.Wearable supercapacitor and self-powered sensing systems have been attracted researchers,because of its excellent energy storage performance and application prospect in health monitoring.Nickel cobalt oxide is widely used in the field of energy storage as a kind of transition metal oxide material with high specific capacitance and environment friendliness.To realize the flexibility and excellent electrochemical performance of nickel-cobalt oxide and apply it to the fields of energy storage and sensing is an important step for the efficient realization of real-time human health monitoring,which is of great significance to the development of wearable electronic devices.The main contents are as follows:（1）Using a simple and efficient electrochemical deposition method,carbon fiber-based NiCoO₂ nanosheets coating with nitrogen-doped carbon（CF@NiCoO₂@N-C）is successfully prepared.Through material characterization and electrochemical test analysis,the excellent electrochemical performance of CF@NiCoO₂@N-C is proved.The specific capacitance is 644mF cm^-2 at the current density of 2 mA cm^-2,which indicates that the flexible electrode has excellent capacitance performance.The electrode remained about 94%capacitance after 10000cycles at the high rate of 10 mA cm^-2,which verified its excellent cycle stability.Due to the woven nature of the carbon fiber substrate,the flexible electrode can be easily integrated into clothing,enabling simple and efficient wearable applications.（2）The CF@N-C flexible electrode is prepared by a similar electrodeposition method and showed excellent capacitance and rate performance.The electrode is used as the negative electrode material of the supercapacitor.The flexible solid asymmetric supercapacitor is assembled with CF@NiCoO₂@N-C and CF@N-C,PVA/KOH is used as solid electrolyte.The specific capacitance is 98.5 mF cm^-2 at the current density of 2 mA cm^-2,which indicates that the device has excellent capacitance performance.Meanwhile,the device combines high capacitance stability（95%capacitance retention after 8000 cycles）and excellent flexibility（95%capacitance retention after 10000 bending cycles）.（3）Self-powered flexible energy device is integrated with flexible solid-state supercapacitors and solar cells.Electrochemical tests have proved its stable output under different conditions,showing its application value in the field of wearable energy storage.Then,the enzyme-free glucose sensor is assembled with the CF@NiCoO₂@N-C flexible electrode,and the sensor showed high sensitivity.The self-powered sensing system is integrated with the self-powered energy device and glucose sensor to realize the remote detection of glucose by the smartphone.