Lithium metal is supposed to be critical material for constructing next-generation batteries due to extremely high capacity and ultralow redox potential. However, the perplexing issue of lithium dendrite growth impede...Lithium metal is supposed to be critical material for constructing next-generation batteries due to extremely high capacity and ultralow redox potential. However, the perplexing issue of lithium dendrite growth impedes the commercial application. The initial nucleation and low Li ions diffusion rate in the electrolyte/electrode interface dominate the deposition behavior. Therefore, a uniform and flexible interface is urgently needed. Here, a facile method is proposed to prepare a thin and porous LiF-rich layer (TPL) by the in-situ reaction of small amount of ammonium hydrogen difluoride (NH4HF2) and Li metal. The deposition morphology on Li metal anode with LiF layer is significantly flat and homogeneous owning to low lateral diffusion barrier on LiF crystals and the porous structure of TPL film. Additionally, the symmetrical cells made with such TPL Li anodes show significantly stable cycling over 100 cycles at high current density of 6 mA/cm^2. The TPL Li|LiFePO4 full cells keep over 99% capacity retention after 100 cycles at 2.0 C. This approach serves as a facile and controllable way of adjusting the protective layer on Li metal.展开更多
The rechargeable aluminum batteries(RAB)have shown great potential for energy storage applications due to their low-cost and superior volumetric capacity.However,the battery performances are far from satisfactory owin...The rechargeable aluminum batteries(RAB)have shown great potential for energy storage applications due to their low-cost and superior volumetric capacity.However,the battery performances are far from satisfactory owing to the poor kinetics of electrode reactions,including the solid-state ionic diffusion and interfacial charge transfer.The charge transfer reaction,typically the cation desolvation at the interface(Helmholtz plane),is crucial for determining the interfacial charge transfer,which induces the solvent effect in batteries but has not been explored in RABs.Herein,we provide a comprehensive understanding of solvent effects on interface kinetics and electrochemical performance of RAB by analyzing the desolvation process and charge transfer energy barrier.The pivotal role of solvent effects is confirmed by the successful application of Al(OTF)_(3)-H_(2)O electrolyte,which displays easy desolvation,low charge transfer resistance,and thus superior Al-ion storage performance over other electrolytes in our studies.In addition,based on the strong correlation between the calculated desolvation energy and charge transfer energy barrier,the calculation of dissociation energy of ion-solvent complex is demonstrated as an efficient index for designing electrolytes.The in-depth understanding of solvent effects provides rational guidance for new electrolyte and RAB design.展开更多
基金supported by the National Basic Research Program of China (Grant no. 2015CB251100)Beijing Natural Science Foundation (No. L182023)
文摘Lithium metal is supposed to be critical material for constructing next-generation batteries due to extremely high capacity and ultralow redox potential. However, the perplexing issue of lithium dendrite growth impedes the commercial application. The initial nucleation and low Li ions diffusion rate in the electrolyte/electrode interface dominate the deposition behavior. Therefore, a uniform and flexible interface is urgently needed. Here, a facile method is proposed to prepare a thin and porous LiF-rich layer (TPL) by the in-situ reaction of small amount of ammonium hydrogen difluoride (NH4HF2) and Li metal. The deposition morphology on Li metal anode with LiF layer is significantly flat and homogeneous owning to low lateral diffusion barrier on LiF crystals and the porous structure of TPL film. Additionally, the symmetrical cells made with such TPL Li anodes show significantly stable cycling over 100 cycles at high current density of 6 mA/cm^2. The TPL Li|LiFePO4 full cells keep over 99% capacity retention after 100 cycles at 2.0 C. This approach serves as a facile and controllable way of adjusting the protective layer on Li metal.
基金This work was supported by the National Natural Science Foundation of China(22075028).
文摘The rechargeable aluminum batteries(RAB)have shown great potential for energy storage applications due to their low-cost and superior volumetric capacity.However,the battery performances are far from satisfactory owing to the poor kinetics of electrode reactions,including the solid-state ionic diffusion and interfacial charge transfer.The charge transfer reaction,typically the cation desolvation at the interface(Helmholtz plane),is crucial for determining the interfacial charge transfer,which induces the solvent effect in batteries but has not been explored in RABs.Herein,we provide a comprehensive understanding of solvent effects on interface kinetics and electrochemical performance of RAB by analyzing the desolvation process and charge transfer energy barrier.The pivotal role of solvent effects is confirmed by the successful application of Al(OTF)_(3)-H_(2)O electrolyte,which displays easy desolvation,low charge transfer resistance,and thus superior Al-ion storage performance over other electrolytes in our studies.In addition,based on the strong correlation between the calculated desolvation energy and charge transfer energy barrier,the calculation of dissociation energy of ion-solvent complex is demonstrated as an efficient index for designing electrolytes.The in-depth understanding of solvent effects provides rational guidance for new electrolyte and RAB design.
