Basic Research On The Application Technology Of Biomass Bamboo Charcoal Materials In Supercapacitors

The supercapacitor,also known as double-layer capacitor or ultracapacitor,differs from a regular capacitor and batteries in that it has a very high capacitance,quick charge/discharge rate and long circle lifetime,etc.A capacitor stores energy by means of a static charge as opposed to an electrochemical reaction.Preparing electrode materials is one of the key techniques for development of supercpacitors.Aiming at solving the mentioned problems above,we fabricated hybrid materials.The major contents are listed follows:?1?At present,carbon materials are the most widely studied and in-depth electrode materials,but the most important problem at present is the economic problem of carbon materials.In this study,the bamboo charcoal raw materials of this study were selected by using five different bamboo,which is widely used in nature,as a raw material.By pre-carbonization-carbonization and subsequent purification treatment,we select bamboo species with excellent performance.The results were as follows.The natural structure of water bamboo provide the ion transport,which makes it the best performance.At a current density of 0.1 A g^-1,the first charge-discharge specific capacitance is 108.2 F g^-1.The 10,000th charge-discharge specific capacitance was 84.5 F g^-1,and the retention rate was 78.1%.?2?The properties of carbon materials obtained by direct carbonization can be further expanded by activation.In this study,three kinds of bamboo carbon with better performance were prepared by physically?CO₂?activated,chemical?KOH?activated and physico-chemical?CO₂+KOH?combined activated methods.The experimental results show that the novel physical-chemical combined activation method used in this study has a significant eftect on the electrochemical performance of carbon materials.At a current density of 0.1 A g^-1,the first charge-discharge specific capacitance is 108.2 F g^-1,and the last charge-discharge specific capacitance is 84.5 F g^-1.The retention rate is 96%.?3?Novel WO₃·2H₂O/BC hybrids were designed and fabricated by a facile y-irradiation strategy.Morphologies and microstructures of the samples were investigated by XRD,SEM,TEM and XPS,while CV,GCD and EIS were carried out to study capacitive properties.The electrochemical results demonstrated that WO₃·2H₂O/BC hybrids delivered a high specific capacity(391 F g^-1 at a current density of 0.5 A g^-1)and excellent cycle stability ?82%retention even after 10,000 cycles?.The synergetic of bamboo?EDLC?and WO₃·2H₂O?pseudocapacitance?provided short ion diffusion paths and facilitates the rapid electronic transport,indicating its good performance for supercapacitor applications.?4?In addition,novel amorphous MnO₂/BC hybrids were designed and fabricated by a facile y-irradiation strategy.Morphologies and microstructures of the samples were investigated by X-ray diffraction?XRD?,field emission scanning electron microscopy?FESEM?and transmission electron microscopy?TEM?,while cyclic voltammetry?CV?,galvanostatic charge/discharge?GCD?and electrochemical impedance spectroscopy?EIS?were carried out to study capacitive properties.The electrochemical results demonstrated that MnO₂ hybrids delivered a high specific capacity(499 F g^-1 at a current density of 0.5 A g^-1)and excellent cycle stability (78%capacitance retention even after 10,000 cycles at 1 A g^-1).The combination of bamboo?EDLC?and MnO₂?pseudocapacitance?provided short ion diffusion paths and rapid electronic transport,indicating good performance for supercapacitor applications.Finally,the fabrication methods,and corresponding enhancement mechanisms of these prepared materials were summarized.The further works were looked forward.