Research On H_xMoO₃ And MoO_3-x Electrode Materials

Supercapacitors（SC）possess high power density,long cycle life and short charge time,which have the potential to cover the gap between energy density and power density.Comparing with the traditional thin film capacitors,electrolytic capacitors and ceramic capacitors,SC are more useful and promising.Due to the excellent power density and cycle life,SC are usually co-used with lithium ion battery.What is more,SC could work individually because of their relativity high energy density.There are various applications of SC,such as consumer electronics,war industry,new energy automobile and rail transit.With the deterioration of environment and energy,and the support of government,SC are going to get fast development.The energy density of metal oxide based SC is higher than carbon SC,which could cover their shortages as much as possible.However,most metal oxides have obvious defects that restrict their use.Thus,this work is aimed to explore a comprehensive electrode material.This work chose MoO₃ and its ramification to research and firstly synthesized the elm seeds-like hierarchical mesoporous H_x MoO₃ nanosheets through a facile hydrothermal method,then treated it in hydrogen atmosphere to get MoO_3-x which remained the same morphology of H_xMoO₃,however,got enhanced electronic conductivity.The well-designed porous structure exposes massive active sites and diffusion paths.The H_x MoO₃ and MoO_3-x electrodes exhibit excellent specific capacitance,especially for MoO_3-x,which delivers an outstanding capacitance of 1480F/g at 5A/g at the potential window of -0.6⁰.2V.More importantly,they show remarkable capacitance retention of more than100%after 10000 cycles at a high scan rate of 100mV/s.Furthermore,we firstly demonstrate the special redox/intercalation pseudocapacitive mechanism towards H⁺electrolyte ions.Our works enriches the characteristic of pseudocapacitive mechanism and provide a promise to fabricate next generation high energy density supercapacitors.