简介：Preparationofhierarchicallyporous,heteroatom-richnanostructuredcarbonsthroughgreenandscalableroutesplaysakeyroleforpracticalenergystorageapplications.Inthiswork,naturallyabundantlignocellulosicagriculturalwastewithhighinitialoxygencontent,hazelnutshells,werehydrothermallycarbonizedandconvertedintonanostructured‘hydrochar’.Environmentallybenignceramic/magnesiumoxide（MgO）templatingwasusedtointroduceporosityintothehydrochar.Electrochemicalperformanceoftheresultingmaterial（HM700）wasinvestigatedinaqueoussolutionsof1MH2SO4,6MKOHand1MNa2SO4,usingathree-electrodecell.HM700achievedahighspecificcapacitanceof323.2F/gin1MH2SO4（at1A/g,-0.3to0.9Vvs.Ag/AgCl）duetothecontributionsofoxygenheteroatoms（13.5wt%）tothetotalcapacitancebypseudo-capacitiveeffect.Moreover,amaximumenergydensityof11.1Wh/kgandamaximumpowerdensityof3686.2W/kgwereattainedforthesymmetricsupercapacitoremployingHM700aselectrodematerial（1MNa2SO4,E=2V）,makingthedevicepromisingforgreensupercapacitorapplications.