This paper clarified the network structure of the lithium-ion battery(LIB)slurry under effects of composite conductive agent amount and carbon black(CB)to graphene(Gr)mass ratio(m'_(CB):m'_(Gr)).Four different...This paper clarified the network structure of the lithium-ion battery(LIB)slurry under effects of composite conductive agent amount and carbon black(CB)to graphene(Gr)mass ratio(m'_(CB):m'_(Gr)).Four different amounts of composite conductive agent which are com1=0.25%,com2=0.5%,com3=0.75%and com4=1%are selected as the conductive materials for LIB slurries.Meanwhile,to discriminate the individual impacts of CB and Gr,two distinct mass ratios of CB to Gr,namely,m'cB:m'cr=1:2 and m'c:m'Gr=2:1,are additionally chosen.Moreover,the influence of single conductive additive agent CB or Gr with the same amount as composite conductive agent on the network structure of the LIB slurry is also investigated.Furthermore,Electrochemical Impedance Spectroscopy(EIS),Scanning Electron Microscopy(SEM)and Raman experiments are performed to obtain the electrochemical,morphological and Raman characterizations of LIB slurry,respectively.After analyzing the experimental results,the main conclusion shows that the synergistic interaction between CB and Gr ensures a high-level conductive effciency because of minimizing the amount of the conductive agent and increasing the amount of LiCoO_(2) particles to the utmost degree,which has the potential to substantially elevating the energy density of LIB.展开更多
This paper proposed an optimal approach to disperse the composite conductive agent which is composed of carbon black(CB)and graphene(Gr)within lithium-ion battery(LIB)slurry with different mixing speeds and mixing tim...This paper proposed an optimal approach to disperse the composite conductive agent which is composed of carbon black(CB)and graphene(Gr)within lithium-ion battery(LIB)slurry with different mixing speeds and mixing times.The internal structures of LIB slurry are characterized by Electrochemical Impedance Spectroscopy,Scanning Electron Microscopy,and Raman experiment.Initially,a composite conductive solution is prepared by mixing the composite conductive agent with NMP solvent under the conditions of five different mixing speeds n_(1)(n_(1)=1000,1100,1200,1300,1400 rpm)in the case of mixing time t_(1)=10 min.Subsequently,LIB slurry is prepared by blending the composite conductive solution,LiCoO_(2)and PVDF-NMP solution under the conditions of five different mixing speeds n_(2)(n_(2)=1000±280,1100±280,1200±280,1300±280,1400±280 rpm)in the case of mixing time t_(2)=6 min.By analyzing the internal structure of different LIB slurries,it shows that in the case of n_(1)=n_(2)=1200 rpm,a conductive network structure is well formed within LIB slurry.Additionally,in order to determine the optimal time to prepare the composite conductive solution for LIB slurry,nine different t_(1)(t_(1)=0,10,20,30,40,50,60,70,80 min)are selected.By analyzing the internal structure of different LIB slurries,a well-formed conductive network structure and a uniformly distributed composite conductive agent are deduced in LIB slurry when t_(1)=50 min.Therefore,it can be concluded that the composite conductive agent composed of CB and Gr is able to be uniformly dispersed in LIB slurry by establishing a well-formed conductive network structure under the optimal mixing speed n_(1)=n_(2)=1200 rpm and the optimal mixing time t_(1)=50 min,t_(2)=6 min.This kind of the internal structure has the potential to be used to further analyze the dispersion characterizations of LIB slurry under different composite conductive agent and CB/Gr ratios with the aim of improving the final performance of LIB.展开更多
Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated us...Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.展开更多
基金support from National Natural Science Foundation of China(grant No.52006176)the Ministry of Education's“Chunhui Plan"Collaborative Research project(grant No.202200491)the Key Research and Development Project of Shaanxi Province(grant No.2022kw-18).
文摘This paper clarified the network structure of the lithium-ion battery(LIB)slurry under effects of composite conductive agent amount and carbon black(CB)to graphene(Gr)mass ratio(m'_(CB):m'_(Gr)).Four different amounts of composite conductive agent which are com1=0.25%,com2=0.5%,com3=0.75%and com4=1%are selected as the conductive materials for LIB slurries.Meanwhile,to discriminate the individual impacts of CB and Gr,two distinct mass ratios of CB to Gr,namely,m'cB:m'cr=1:2 and m'c:m'Gr=2:1,are additionally chosen.Moreover,the influence of single conductive additive agent CB or Gr with the same amount as composite conductive agent on the network structure of the LIB slurry is also investigated.Furthermore,Electrochemical Impedance Spectroscopy(EIS),Scanning Electron Microscopy(SEM)and Raman experiments are performed to obtain the electrochemical,morphological and Raman characterizations of LIB slurry,respectively.After analyzing the experimental results,the main conclusion shows that the synergistic interaction between CB and Gr ensures a high-level conductive effciency because of minimizing the amount of the conductive agent and increasing the amount of LiCoO_(2) particles to the utmost degree,which has the potential to substantially elevating the energy density of LIB.
基金the support from National Natural Science Foundation of China(grant No.52006176)the Ministry of Education's“Chunhui Plan”Collaborative Research project(grant No.202200491)the Key Research and Development Project of Shaanxi Province(grant No.2022kw-18).
文摘This paper proposed an optimal approach to disperse the composite conductive agent which is composed of carbon black(CB)and graphene(Gr)within lithium-ion battery(LIB)slurry with different mixing speeds and mixing times.The internal structures of LIB slurry are characterized by Electrochemical Impedance Spectroscopy,Scanning Electron Microscopy,and Raman experiment.Initially,a composite conductive solution is prepared by mixing the composite conductive agent with NMP solvent under the conditions of five different mixing speeds n_(1)(n_(1)=1000,1100,1200,1300,1400 rpm)in the case of mixing time t_(1)=10 min.Subsequently,LIB slurry is prepared by blending the composite conductive solution,LiCoO_(2)and PVDF-NMP solution under the conditions of five different mixing speeds n_(2)(n_(2)=1000±280,1100±280,1200±280,1300±280,1400±280 rpm)in the case of mixing time t_(2)=6 min.By analyzing the internal structure of different LIB slurries,it shows that in the case of n_(1)=n_(2)=1200 rpm,a conductive network structure is well formed within LIB slurry.Additionally,in order to determine the optimal time to prepare the composite conductive solution for LIB slurry,nine different t_(1)(t_(1)=0,10,20,30,40,50,60,70,80 min)are selected.By analyzing the internal structure of different LIB slurries,a well-formed conductive network structure and a uniformly distributed composite conductive agent are deduced in LIB slurry when t_(1)=50 min.Therefore,it can be concluded that the composite conductive agent composed of CB and Gr is able to be uniformly dispersed in LIB slurry by establishing a well-formed conductive network structure under the optimal mixing speed n_(1)=n_(2)=1200 rpm and the optimal mixing time t_(1)=50 min,t_(2)=6 min.This kind of the internal structure has the potential to be used to further analyze the dispersion characterizations of LIB slurry under different composite conductive agent and CB/Gr ratios with the aim of improving the final performance of LIB.
基金supported by the National Key Research and Development Program of China,China(2019YFA0705102)the National Natural Science Foundation of China,China(22179144,22005332)。
文摘Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.
