Scalable and fast fabrication of graphene integrated micro-supercapacitors with remarkable volumetric capacitance and flexibility through continuous centrifugal coating

Microscale electrochemical energy storage devices,e.g., micro-supercapacitors(MSCs),possessing tailored performance and diversified form factors of lightweight,miniaturization,flexibility and exceptional integration are highly necessary for the smart power sources-unitized electronics.Despite the great progress,the fabrication of MSCs combining high integration with high volumetric performance remains largely unsolved.Herein,we develop a simple,fast and scalable strategy to fabricate graphene based highly integrated MSCs by a new effective continuous centrifugal coating technique.Notably,the resulting highly conductive graphene films can act as not only patterned microelectrodes but also metal-free current collectors and interconnects,endowing modular MSCs with high integrity,remarkable flexibility,tailored voltage and capacitance output,and outstanding performance uniformity.More importantly,the strong centrifugal force and shear force generated in continuous centrifugal coating process lead to graphene films with high alignment,compactness and packing density,contributing to excellent volumetric capacitance of ~31.8 F cm^(-3) and volumetric energy density of ~2.8 mWh cm^(-3),exceeding most reported integrated MSCs.Therefore,our work paves a novel way for simple and scalable fabrication of integrated MSCs and offers promising opportunities as standalone microscale power sources for new-generation electronics.

Ti,F Codoped Sodium Manganate of Layered P2-Na_(0.7)MnO_(2.05)Cathode for High Capacity and Long-Life Sodium-Ion Battery

The development of layered sodium manganese oxide cathode materials with high capacity and structural stability is one of the keys to boosting the performance of sodium-ion batteries(SIBs),but it remains a great challenge.Herein,a titanium and fluorine codoped P2 type sodiummanganate of Na_(0.7)MnO_(2.05)cathode material(NMO-0.1TF)is developed as a high-capacity and long-durable cathode for highperformance SIBs.Titanium and fluorine codoping significantly reduces the structural deformation,synergistically improves structural stabilization,inhibits the formation of irreversible phases,and enhances electrochemical kinetics.As a result,the NMO-0.1TF||Na battery working in the voltage ranges of 2.0-4.2 V exhibits a high specific capacity of 227 mAh g^(−1)at a current density of 20 mA g^(−1)and an excellent rate performance(76 mAh g^(−1)at a high current density of 3 A g^(−1)).Such a battery still delivers an outstanding cycle stability,shows a high initial discharge capacity of 133 mAh g^(−1)at 1 A g^(−1),and maintains the initial capacity of 96.2%after 200 cycles.More importantly,the assembled full battery of NMO-0.1TF||hard carbon validates high capacity and impressive cyclability.Therefore,this codoped NMO-0.1TF cathode with high capacity and excellent stability represents a brilliantly practical application for developing high energy density SIBs.

Sepiolite/Cu_2O/Cu photocatalyst: Preparation and high performance for degradation of organic dye

A novel ternary sepiolite/Cu_2O/Cu(SCC) nanocomposite was successfully synthesized by a facile one-pot method. The Cu_2O/Cu nanoparticles in the SCC nanocomposite are well dispersed on the sepiolite surface. It exhibited enhanced photocatalytic performance in the degradation of congo red(CR), remarkably superior to that of Cu_2O or Cu_2O/Cu nanoparticles. Elemental copper in the SCC serves as a good electron acceptor to promote the transfer of photo-generated electrons in Cu_2O and suppress the recombination of the photo-generated electrons and holes of the composite. The enhanced photocatalytic efficiency is attributed to the synergistic effect of sepiolite and Cu_2O/Cu. This type of SCC nanocomposites is a promising candidate as photocatalytic material for environmental protection.