This study computationally investigates the hydrodynamics of different serpentine flow field designs for redox flow batteries,which considers the Poiseuille flow in the flow channel and the Darcy flow porous substrate...This study computationally investigates the hydrodynamics of different serpentine flow field designs for redox flow batteries,which considers the Poiseuille flow in the flow channel and the Darcy flow porous substrate.Computational Fluid Dynamics(CFD)results of the in-house developed code based on Finite Volume Method(FVM)for conventional serpentine flow field(CSFF)agreed well with those obtained via experiment.The deviation for pressure drop(ΔP)was less than 5.1%for all the flow rates,thus proving the present CFD analysis’s validity on the modified variation of serpentine flow fields.Modified serpentine flow field-2(MSFF2)design provided least pressure drop across the channel and maximum velocity penetration across the porous substrate when compared to the other designs.This increases its wetting ability,which is very important in terms of mass transfer over potential for electrochemical reaction happening in the porous substrate to achieve effective electrochemical cell performance.展开更多
VS2 with natural layered structure and metallic conductivity is a prospective candidate for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).However,due to large radius of Na+and K+,the limited interlayer s...VS2 with natural layered structure and metallic conductivity is a prospective candidate for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).However,due to large radius of Na+and K+,the limited interlayer spacing(0.57 nm)of VS2 generally determines high ion diffusion barrier and large volume variation,resulting in unsatisfactory electrochemical performance of SIBs and PIBs.In this work,flower-like VS_(2)/N-doped carbon(VS_(2)/N-C)with expanded(001)plane is grown on reduced graphene oxide(rGO)via a solvothermal and subsequently carbonization strategy.In the VS_(2)/N-C@rGO nanohybrids,the ultrathin VS2"petals"are alternately intercalated by the N-doped porous carbon monolayers to achieve an expanded interlayer spacing(1.02 nm),which can effectively reduce ions diffusion barrier,expose abundant active sites for Na+/K+intercalation,and tolerate large volume variation.The N-C and rGO carbonous materials can significantly promote the electrical conductivity and structural stability.Benefited from the synergistic effect,the VS2/N-C@rGO electrode exhibits large reversible capacity(Na+:407 mAh·g^(-1) at 1 A·g^(-1);K^(+):334 mAh·g^(-1) at 0.2 A·g^(-1)),high rate capacity(Na+:273 mAh·g^(-1) at 8 A·g^(-1);K+:186 mAh·g^(-1) at 5 A·g^(-1)),and remarkable cycling stability(Na+:316 mAh·g^(-1) at 2 A·g^(-1) after 1,400 cycles;K^(+):216 mAh·g^(-1) at 1 A·g^(-1) after 500 cycles).展开更多
基金The authors gratefully thank the Centre for Incubation,Innovation,Research and Consultancy(CIIRC),Jyothy Institute of Technology and Sri Sringeri Sharadha Peetam for supporting this research.K.Kadirgama would like to acknowledge Malaysia Minister of Higher Education for providing financial assistant under Fundamental Research Grant Scheme(FRGS)No.FRGS/1/2019/TK07/UMP/02/3Universiti Malaysia Pahang(UMP)under Grant No.RDU192207.
文摘This study computationally investigates the hydrodynamics of different serpentine flow field designs for redox flow batteries,which considers the Poiseuille flow in the flow channel and the Darcy flow porous substrate.Computational Fluid Dynamics(CFD)results of the in-house developed code based on Finite Volume Method(FVM)for conventional serpentine flow field(CSFF)agreed well with those obtained via experiment.The deviation for pressure drop(ΔP)was less than 5.1%for all the flow rates,thus proving the present CFD analysis’s validity on the modified variation of serpentine flow fields.Modified serpentine flow field-2(MSFF2)design provided least pressure drop across the channel and maximum velocity penetration across the porous substrate when compared to the other designs.This increases its wetting ability,which is very important in terms of mass transfer over potential for electrochemical reaction happening in the porous substrate to achieve effective electrochemical cell performance.
基金The authors are grateful to the National Key Research and Development Project(No.51890863)the National Natural Science Foundation of China(NSFC,Nos.51872172 and 51972197)+2 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2018MEM010 and ZR2019MEM021)Major Research and Development Program for Public Welfare in Shandong(No.2018GGX102021)Young Scholars Program of Shandong University.
文摘VS2 with natural layered structure and metallic conductivity is a prospective candidate for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).However,due to large radius of Na+and K+,the limited interlayer spacing(0.57 nm)of VS2 generally determines high ion diffusion barrier and large volume variation,resulting in unsatisfactory electrochemical performance of SIBs and PIBs.In this work,flower-like VS_(2)/N-doped carbon(VS_(2)/N-C)with expanded(001)plane is grown on reduced graphene oxide(rGO)via a solvothermal and subsequently carbonization strategy.In the VS_(2)/N-C@rGO nanohybrids,the ultrathin VS2"petals"are alternately intercalated by the N-doped porous carbon monolayers to achieve an expanded interlayer spacing(1.02 nm),which can effectively reduce ions diffusion barrier,expose abundant active sites for Na+/K+intercalation,and tolerate large volume variation.The N-C and rGO carbonous materials can significantly promote the electrical conductivity and structural stability.Benefited from the synergistic effect,the VS2/N-C@rGO electrode exhibits large reversible capacity(Na+:407 mAh·g^(-1) at 1 A·g^(-1);K^(+):334 mAh·g^(-1) at 0.2 A·g^(-1)),high rate capacity(Na+:273 mAh·g^(-1) at 8 A·g^(-1);K+:186 mAh·g^(-1) at 5 A·g^(-1)),and remarkable cycling stability(Na+:316 mAh·g^(-1) at 2 A·g^(-1) after 1,400 cycles;K^(+):216 mAh·g^(-1) at 1 A·g^(-1) after 500 cycles).
