Green fabrication of hierarchically porous carbon microtubes from biomass waste via self-activation for high-energy-density supercapacitor

Oxygen-rich hierarchical porous carbon nanosheets derived from the KOH/KNO3 co-activation treatment of soybean straw for high-performance supercapacitors

“…The spectra could be split into four types of functional groups including sp 2 -C, sp 3 -C, CO, and O–CO, corresponding to the peaks located at 283.98 eV, 284.80 eV, 286.11 eV, and 288.76 eV, respectively. 8,36 Among them, sp 2 -C and sp 3 -C individually indicate basal plane carbon and defective carbon, respectively, while CO refers to carbonyl, ketone, or aldehyde; and O–CO represents carboxyl, carboxylic anhydride, or ester. 9,10 Compared to SSC2-0, the three co-activated samples (SSC2- X ( X = 0.5, 0.6, and 0.7)) exhibited significantly increased sp 3 -C, CO and O–CO contents together with a remarkable reduction in sp 2 -C moieties, which can be attributed to the breaking of the chemical bond in the carbon lattice caused by the rapid volume explosion and strong oxidative etching effect originating from KNO 3 .…”

Flexible All-Solid-State Asymmetric Supercapacitors Based on PPy-Decorated SrFeO3−δ Perovskites on Carbon Cloth

“…The simulated equivalent circuits include equivalent series resistance ( R s ), charge-transfer resistance ( R ct ), and Warburg impedance ( W o ). The internal resistance R s is characterized by the intercept of the semicircle with the horizontal axis in the high-frequency region . The R s value of each electrode is close to 0.80 Ω, indicating that the electrode material has a good electrical conductivity.…”

“…Electronic devices are facing higher requirements to adapt to different environments. − As wearable and portable electronic devices develop, new challenges such as a mechanically robust, flexible, and high power density arise for the corresponding energy supply system. , Supercapacitors offer higher power density and better cycle life than traditional batteries. , However, the low energy density restricts their practical application in powering portable devices. − It is well-known that electrodes with advanced mechanical and electrochemical features are crucial for flexible supercapacitors. Various strategies, such as morphological control, porous structure construction, and composite design, have been widely investigated and applied to enhance the electrochemical performance of flexible electrode materials. − …”

Sustainable Biochar Nanosheets Derived from Sweet Sorghum Residues via Superbase Pretreatment

“…The N 2 adsorption−desorption isotherms of all biochar samples displayed typical adsorption curves of type I + IV isotherms, demonstrating the presence of micropores and mesopores (Figure S7). 33 As seen in Table S2, SC-800 exhibited the largest surface area of ∼279.09 m 2 /g compared with SC-D-800 (∼265.01 m 2 /g), SC-K-800 (∼249.28 m 2 /g), and SC-D/K-800 (∼203.10 m 2 /g), which might be attributed to the generation of micropores/mesopores by self-activating natural minerals, such as potassium, zinc, and phosphate in raw SS. 34 The effects of temperatures on the formation of sheet-like biochar were further investigated.…”