Gel polymer electrolytes(GPEs)with high flame‐retardant concentration can remarkably reduce the thermal runaway risk of lithium metal batteries(LMBs).However,higher flame‐retardant content in GPEs always leads to in...Gel polymer electrolytes(GPEs)with high flame‐retardant concentration can remarkably reduce the thermal runaway risk of lithium metal batteries(LMBs).However,higher flame‐retardant content in GPEs always leads to increased leakage of active component and severe lithium corrosion,which greatly hinders the service life of LMBs.Herein,GPEs with high‐loading triphenyl phosphate(TPP)are originally fabricated by coaxial electrospinning and stabilized by dual confinement effects,including chemisorption of polyvinylidene fluoride‐hexafluoropropylene(PVDF‐HFP),and physical encapsulation of polyacrylonitrile(PAN)/PVDF‐HFP.These effects arise from the strong polar interactions between the−CF3 group in PVDF‐HFP and P=O group in TPP,as well as the superior anti‐swelling property of PAN.To mitigate TPP‐induced corrosion during cycling,the optimized Li anode is armored with LiF‐rich solid electrolyte interphase(SEI)layer through immersing it in fluoroethylene carbonate‐containing electrolyte.As expected,the corresponding Li||Li symmetric cells deliver long‐term stable cycling behavior over 2400 h at 0.5 mA cm−2,and the LiFePO4||Li batteries hold a high‐capacity retention ratio of 81.7%after 6000 cycles at 10 C with excellent flame retardancy.These findings offer new insight into designing the SEI layer for lithium metal in flame‐retardant electrolytes,thus promoting the development and application of high‐security LMBs.展开更多
The practical deployment of lithium-sulfur(Li-S)batteries is impeded by severe polysulfide shuttle effects and sluggish redox kinetics.The use of heterostructures as catalysts in sulfur hosts is expected to improve th...The practical deployment of lithium-sulfur(Li-S)batteries is impeded by severe polysulfide shuttle effects and sluggish redox kinetics.The use of heterostructures as catalysts in sulfur hosts is expected to improve the electrochemical performance of Li-S batteries.However,single heterostructures still suffer from the fatal problems of few active sites and high charge transfer barriers.Herein,defect-engineered MoO_(2-x)-Mo_(2)C@NC(NC is the abbreviation form of nitrogendoped carbon)is designed as an efficient electrocatalyst to adjust the surface properties and electron distribution of the heterostructure by introducing a defective structure into the heterostructure,thereby enhance active site exposure.The dorbitals of Mo_(2)C facilitate strong interactions with the p-electrons of MoO_(2),enabling efficient electron transfer between reactants and active sites.DFT calculations confirm the interaction of the d orbitals of Mo_(2)C with the p electrons in the MoO_(2)material,effectively lowering the reaction energy barrier.As a result,the S/MoO_(2-x)-Mo_(2)C@NC exhibits remarkable cycle stability,retaining a specific capacity of 714 mAh·g^(-1)after 500 cycles at 0.5 C.This work provides insights into defectdriven heterostructure design for advanced Li-S batteries.展开更多
基金supported by the National Natural Science Foundation of China (52404316, 52474325)the S&T program of Hebei Province(225A4404D)+3 种基金the Natural Science Foundation of Hainan Province (524RC475)the Collaborative Innovation Center of Marine Science and Technology of Hainan University (XTCX2022HYC14)the Xingtai City Natural Science Foundation (2023ZZ027)The Pico Electron Microscopy Center of Hainan University partially supported this study
文摘Gel polymer electrolytes(GPEs)with high flame‐retardant concentration can remarkably reduce the thermal runaway risk of lithium metal batteries(LMBs).However,higher flame‐retardant content in GPEs always leads to increased leakage of active component and severe lithium corrosion,which greatly hinders the service life of LMBs.Herein,GPEs with high‐loading triphenyl phosphate(TPP)are originally fabricated by coaxial electrospinning and stabilized by dual confinement effects,including chemisorption of polyvinylidene fluoride‐hexafluoropropylene(PVDF‐HFP),and physical encapsulation of polyacrylonitrile(PAN)/PVDF‐HFP.These effects arise from the strong polar interactions between the−CF3 group in PVDF‐HFP and P=O group in TPP,as well as the superior anti‐swelling property of PAN.To mitigate TPP‐induced corrosion during cycling,the optimized Li anode is armored with LiF‐rich solid electrolyte interphase(SEI)layer through immersing it in fluoroethylene carbonate‐containing electrolyte.As expected,the corresponding Li||Li symmetric cells deliver long‐term stable cycling behavior over 2400 h at 0.5 mA cm−2,and the LiFePO4||Li batteries hold a high‐capacity retention ratio of 81.7%after 6000 cycles at 10 C with excellent flame retardancy.These findings offer new insight into designing the SEI layer for lithium metal in flame‐retardant electrolytes,thus promoting the development and application of high‐security LMBs.
基金the National Natural Science Foundation of China(52474325)Science Research Project of Hebei Education Department(QN2024087)+4 种基金S&T program of Hebei Province(225A4404D)Natural Science Foundation of Hainan Province(524RC475)Collaborative Innovation Center of Marine Science and Technology of Hainan University(XTCX2022HYC14)Xingtai City Natural Science Foundation(2023ZZ027)supported by the Pico Election Microscopy Center of Hainan University.
文摘The practical deployment of lithium-sulfur(Li-S)batteries is impeded by severe polysulfide shuttle effects and sluggish redox kinetics.The use of heterostructures as catalysts in sulfur hosts is expected to improve the electrochemical performance of Li-S batteries.However,single heterostructures still suffer from the fatal problems of few active sites and high charge transfer barriers.Herein,defect-engineered MoO_(2-x)-Mo_(2)C@NC(NC is the abbreviation form of nitrogendoped carbon)is designed as an efficient electrocatalyst to adjust the surface properties and electron distribution of the heterostructure by introducing a defective structure into the heterostructure,thereby enhance active site exposure.The dorbitals of Mo_(2)C facilitate strong interactions with the p-electrons of MoO_(2),enabling efficient electron transfer between reactants and active sites.DFT calculations confirm the interaction of the d orbitals of Mo_(2)C with the p electrons in the MoO_(2)material,effectively lowering the reaction energy barrier.As a result,the S/MoO_(2-x)-Mo_(2)C@NC exhibits remarkable cycle stability,retaining a specific capacity of 714 mAh·g^(-1)after 500 cycles at 0.5 C.This work provides insights into defectdriven heterostructure design for advanced Li-S batteries.
