Regulating the nucleation and growth of Li metal is crucial for achieving stable high-energy-density Li metal batteries(LMBs)without dendritic Li growth,severe volume expansion,and“dead Li”accumulation.Herein,we pre...Regulating the nucleation and growth of Li metal is crucial for achieving stable high-energy-density Li metal batteries(LMBs)without dendritic Li growth,severe volume expansion,and“dead Li”accumulation.Herein,we present a modulation layer composed of porous SnP_(0.94)/CoP p-n heterojunction particles(SCP),synthesized applying the Kirkendall effect.The unique heterointerfaces in the SCP induce a fully ionized depletion region and built-in electric field.This provides strong Li affinity,additional adsorption sites,and facilitated electron transfer,thereby guiding dendrite-free Li nucleation/growth with a low Li deposition overpotential.Moreover,the strategic design of the SCP,accounting for its reaction with Li,yields electronically conductive Co,lithiophilic Li-Sn alloy,and ionic conductive Li_(3)P during progressive cycles.The mixed electronic and ionic conductor(MEIC)ensure the long-term stability of the SCP modulation layer.With this layer,the SCP@Li symmetric cell maintains a low overpotential for 750 cycles even at a high current density of 5 mA cm^(-2).Additionally,the LiFePO_(4)//SCP@Li full cell achieves an imperceptible capacity decay of 0.03%per cycle for 800 cycles at 0.5 C.This study provides insight into MEIC heterostructures for high-performance LMBs.展开更多
Despite great advancements in organic mixed ionic-electronic conductors(OMIECs),their applications remain predominantly restricted to three-electrode organic electro-chemical transistors(OECTs),which rely on an additi...Despite great advancements in organic mixed ionic-electronic conductors(OMIECs),their applications remain predominantly restricted to three-electrode organic electro-chemical transistors(OECTs),which rely on an additional electrolyte layer to balance ionic and electronic transport,resulting in indirect coupling of charge carriers.While direct coupling has the potential to greatly simplify device architectures,it remains underexplored in OMIECs due to the inherent imbalance between electronic and ionic conductivities.In this study,we introduce a straightforward approach to achieve balanced OMIECs and employ them as channel materials in two-electrode organic electrochemical memristors.These devices provide clear evidence of direct coupling between electronic and ionic carriers and exhibit exceptional performance in synaptic device applications.Our findings offer new insights into charge carrier transport mechanisms in OMIECs and establish organic electrochemical memristors as a promising new class of organic electronic devices for next-generation neuromorphic applications.展开更多
The use of samarium-doped ceria (SDC) electrolytes in SOFCs (solid oxide fuel cells) lowers the open circuit voltage (OCV) below the Nernst voltage (Vth). The OCV is calculated with Wagner’s equation which is include...The use of samarium-doped ceria (SDC) electrolytes in SOFCs (solid oxide fuel cells) lowers the open circuit voltage (OCV) below the Nernst voltage (Vth). The OCV is calculated with Wagner’s equation which is included in NernstPlanck equation. Considering the separation of Boltzmann distribution, the fundamental basis of this topic is discussed. A constant voltage loss without leakage currents due to a mixed ionic and electronic conducting (MIEC) dense anode was explained. Only carrier species having sufficient energy to overcome the activation energy can contribute to current conduction, which is determined by incorporating a different constant in the definitions of chemical potential and electrical potential. This difference explains the results using dense MIEC anodes. This topic is not an isolated and minor topic, but of vital importance to electrochemical engineering for the 21st Century.展开更多
BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tun...BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tuned by cationic substitution.Our first-principle calculations show that Ag is a promising substitute for the Fe site,resulting in a reduced oxygen vacancy formation energy compared with the pristine BaFeO_(3-δ).Ag has limited solubility in perovskites,and its introduction generates an Ag metal secondary phase,which influences the cathode performances.In this work,we investigate the matter,using a Ba0:9La0:1Fe_(1-x)AgxO_(3-δ)series of materials as a case study.Acknowledging the limited solubility of Ag in Ba0:9La0:1Fe_(1-x)AgxO_(3-δ),we aim to distinguish the effects of Ag substitution from those of the Ag secondary phase.We observed that Ag substitution increases the number of oxygen vacancies,confirming our calculations,and facilitates the oxygen incorporation.However,Ag substitution lowers the number of holes,in this way reducing the electronic p-type conductivity.On the other hand,Ag metal positively affects the electronic conductivity and helps the redistribution of the electronic charge at the cathode-electrolyte interface.展开更多
基金supported by the Basic Science Research Program through National Research Foundation of Korea(NRF)grant funded by the Ministry of Education(RS-2020-NR049594)the Ministry of Science and ICT(RS-2022-NR070534).
文摘Regulating the nucleation and growth of Li metal is crucial for achieving stable high-energy-density Li metal batteries(LMBs)without dendritic Li growth,severe volume expansion,and“dead Li”accumulation.Herein,we present a modulation layer composed of porous SnP_(0.94)/CoP p-n heterojunction particles(SCP),synthesized applying the Kirkendall effect.The unique heterointerfaces in the SCP induce a fully ionized depletion region and built-in electric field.This provides strong Li affinity,additional adsorption sites,and facilitated electron transfer,thereby guiding dendrite-free Li nucleation/growth with a low Li deposition overpotential.Moreover,the strategic design of the SCP,accounting for its reaction with Li,yields electronically conductive Co,lithiophilic Li-Sn alloy,and ionic conductive Li_(3)P during progressive cycles.The mixed electronic and ionic conductor(MEIC)ensure the long-term stability of the SCP modulation layer.With this layer,the SCP@Li symmetric cell maintains a low overpotential for 750 cycles even at a high current density of 5 mA cm^(-2).Additionally,the LiFePO_(4)//SCP@Li full cell achieves an imperceptible capacity decay of 0.03%per cycle for 800 cycles at 0.5 C.This study provides insight into MEIC heterostructures for high-performance LMBs.
基金supported by the National Natural Science Foundation of China(4020969,62405044,and 52173156)Fund by Science Research Project of Hebei Education Department(HY2024050011)+1 种基金Natural Science Foundation of Sichuan Province(25NSFSC1287)Foundation of Yanshan University(1050030 and 8190299).
文摘Despite great advancements in organic mixed ionic-electronic conductors(OMIECs),their applications remain predominantly restricted to three-electrode organic electro-chemical transistors(OECTs),which rely on an additional electrolyte layer to balance ionic and electronic transport,resulting in indirect coupling of charge carriers.While direct coupling has the potential to greatly simplify device architectures,it remains underexplored in OMIECs due to the inherent imbalance between electronic and ionic conductivities.In this study,we introduce a straightforward approach to achieve balanced OMIECs and employ them as channel materials in two-electrode organic electrochemical memristors.These devices provide clear evidence of direct coupling between electronic and ionic carriers and exhibit exceptional performance in synaptic device applications.Our findings offer new insights into charge carrier transport mechanisms in OMIECs and establish organic electrochemical memristors as a promising new class of organic electronic devices for next-generation neuromorphic applications.
文摘The use of samarium-doped ceria (SDC) electrolytes in SOFCs (solid oxide fuel cells) lowers the open circuit voltage (OCV) below the Nernst voltage (Vth). The OCV is calculated with Wagner’s equation which is included in NernstPlanck equation. Considering the separation of Boltzmann distribution, the fundamental basis of this topic is discussed. A constant voltage loss without leakage currents due to a mixed ionic and electronic conducting (MIEC) dense anode was explained. Only carrier species having sufficient energy to overcome the activation energy can contribute to current conduction, which is determined by incorporating a different constant in the definitions of chemical potential and electrical potential. This difference explains the results using dense MIEC anodes. This topic is not an isolated and minor topic, but of vital importance to electrochemical engineering for the 21st Century.
基金The authors gratefully acknowledge the Research Grant Council of Hong Kong for support through the projects 16201820,and 16206019.
文摘BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tuned by cationic substitution.Our first-principle calculations show that Ag is a promising substitute for the Fe site,resulting in a reduced oxygen vacancy formation energy compared with the pristine BaFeO_(3-δ).Ag has limited solubility in perovskites,and its introduction generates an Ag metal secondary phase,which influences the cathode performances.In this work,we investigate the matter,using a Ba0:9La0:1Fe_(1-x)AgxO_(3-δ)series of materials as a case study.Acknowledging the limited solubility of Ag in Ba0:9La0:1Fe_(1-x)AgxO_(3-δ),we aim to distinguish the effects of Ag substitution from those of the Ag secondary phase.We observed that Ag substitution increases the number of oxygen vacancies,confirming our calculations,and facilitates the oxygen incorporation.However,Ag substitution lowers the number of holes,in this way reducing the electronic p-type conductivity.On the other hand,Ag metal positively affects the electronic conductivity and helps the redistribution of the electronic charge at the cathode-electrolyte interface.
