Garnet-type solid-state electrolytes(SSEs)are particularly attractive in the construction of all-solid-state lithium(Li)batteries due to their high ionic conductivity,wide electrochemical window and remarkable(electro...Garnet-type solid-state electrolytes(SSEs)are particularly attractive in the construction of all-solid-state lithium(Li)batteries due to their high ionic conductivity,wide electrochemical window and remarkable(electro)chemical stability.However,the intractable issues of poor cathode/garnet interface and general low cathode loading hinder their practical application.Herein,we demonstrate the construction of a reinforced cathode/garnet interface by spark plasma sintering,via co-sintering Li_(6.5)La_(3)Zr_(1.5)Ta_(0.5)O_(12)(LLZTO)electrolyte powder and LiCoO_(2)/LLZTO composite cathode powder directly into a dense dual-layer with 5 wt%Li_(3)BO_(3)as sintering additive.The bulk composite cathode with LiCoO_(2)/LLZTO cross-linked structure is firmly welded to the LLZTO layer,which optimizes both Li-ion and electron transport.Therefore,the one-step integrated sintering process implements an ultra-low cathode/garnet interfacial resistance of 3.9Ωcm^(2)(100◦C)and a high cathode loading up to 2.02 mAh cm^(−2).Moreover,the Li_(3)BO_(3)reinforced LiCoO_(2)/LLZTO interface also effectively mitigates the strain/stress of LiCoO_(2),which facilitates the achieving of superior cycling stability.The bulk-type Li|LLZTO|LiCoO_(2)-LLZTO full cell with areal capacity of 0.73 mAh cm^(−2)delivers capacity retention of 81.7%after 50 cycles at 100μA cm^(−2).Furthermore,we reveal that non-uniform Li plating/stripping leads to the formation of gaps and finally results in the separation of Li and LLZTO electrolyte during long-term cycling,which becomes the dominant capacity decay mechanism in high-capacity full cells.This work provides insight into the degradation of Li/SSE interface and a strategy to radically improve the electrochemical performance of garnet-based all-solid-state Li batteries.展开更多
基金This work was supported by the National Key R&D Program of China(Grant No.2021YFB2401800)the National Natural Science Foundation of China(Grants Nos.21875196,22279108,21935009 and 22021001)the Fundamental Research Funds for Xiamen University(No.20720202019).
文摘Garnet-type solid-state electrolytes(SSEs)are particularly attractive in the construction of all-solid-state lithium(Li)batteries due to their high ionic conductivity,wide electrochemical window and remarkable(electro)chemical stability.However,the intractable issues of poor cathode/garnet interface and general low cathode loading hinder their practical application.Herein,we demonstrate the construction of a reinforced cathode/garnet interface by spark plasma sintering,via co-sintering Li_(6.5)La_(3)Zr_(1.5)Ta_(0.5)O_(12)(LLZTO)electrolyte powder and LiCoO_(2)/LLZTO composite cathode powder directly into a dense dual-layer with 5 wt%Li_(3)BO_(3)as sintering additive.The bulk composite cathode with LiCoO_(2)/LLZTO cross-linked structure is firmly welded to the LLZTO layer,which optimizes both Li-ion and electron transport.Therefore,the one-step integrated sintering process implements an ultra-low cathode/garnet interfacial resistance of 3.9Ωcm^(2)(100◦C)and a high cathode loading up to 2.02 mAh cm^(−2).Moreover,the Li_(3)BO_(3)reinforced LiCoO_(2)/LLZTO interface also effectively mitigates the strain/stress of LiCoO_(2),which facilitates the achieving of superior cycling stability.The bulk-type Li|LLZTO|LiCoO_(2)-LLZTO full cell with areal capacity of 0.73 mAh cm^(−2)delivers capacity retention of 81.7%after 50 cycles at 100μA cm^(−2).Furthermore,we reveal that non-uniform Li plating/stripping leads to the formation of gaps and finally results in the separation of Li and LLZTO electrolyte during long-term cycling,which becomes the dominant capacity decay mechanism in high-capacity full cells.This work provides insight into the degradation of Li/SSE interface and a strategy to radically improve the electrochemical performance of garnet-based all-solid-state Li batteries.
