Two flowers per seed:Derivatives of CoG@F127/GO with enhanced catalytic performance of overall water splitting

In this work,cobalt glycerate(CoG@F127)nanosheets grown on the surface of graphene oxide(GO),i.e.CoG@F127/GO,have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method.After calcination,CoG@F127/GO is transformed into one derivative,Co nanoparticles coated with a trace amount of carbon(Co-C)on GO(Co-C/GO).The Co nanoparticles consist of an atypical core-shell structure,in which the core and the shell are both Co.Co-C anchored on GO can avoid the nanoparticles aggregation and expose more active sites for hydrogen evolution reaction(HER)to significantly improve the catalyst activity of HER.CoG@F127/GO is phosphatized to form the other derivate,cobalt pyrophosphate coated with a small amount of carbon(Co_(2)P_(2)O_(7)-C)on GO(Co_(2)P_(2)O_(7)-C/GO).Co_(2)P_(2)O_(7)-C/GO composite owns a large electrochemical active surface area(ECSA)and fast rate towards oxygen evolution reaction(OER).Furthermore,the two derivatives of CoG@F127/GO,i.e.Co-C/GO and Co_(2)P_(2)O_(7)-C/GO as twin flowers,are assembled into an overall water splitting electrolytic cell with a cell voltage of 1.56 V to deliver a current density of 10 mA cm^(-2).

An aqueous rechargeable Fe//LiMn_(2)O_()hybrid battery with superior electrochemical performance beyond mainstream Fe-based batteries

Aqueous rechargeable batteries(ARBs)are generally safer than non-aqueous analogues,they are also less-expensive,and more friendly to the environment.However,the inherent disadvantage of the narrow electrochemical window of H2O seriously restricts the energy density and output voltage of ARBs,especially aqueous rechargeable Fe-based batteries.Herein,we introduce a new battery system:the anode contains C@Fe/Fe_(2)O_(3)composite,which is interfaced with an alkaline electrolyte;the cathode contains LiMn_(2)O_()in contact with a neutral electrolyte.A Li^(+)-conducting membrane is carefully selected to decouple the electrode-electrolyte,which effectively widens the electrochemical window to above 2.65 V,thereby enables an aqueous rechargeable iron battery.Its average output voltage is 1.83 V and its energy density is 235.3 Wh/kg at 549 W/kg.In this work,we propose the energy storage mechanism with the aid of density functional theory(DFT).The calculated reduction potential of the anode agrees with the experimental value.Furthermore,this battery system demonstrates long cycle lifespan of approximately 2500 cycles at 2 A/g,corresponding to a capacity retention of 82.1%.These results are very far superior than those of mainstream aqueous rechargeable Fe-based batteries,which guarantee future investigation for storing electricity energy.