“Dendrite-free”deposition behavior of Mg^(2+)is expected to achieve planar and dense Mg growth for long-life and safe Mg batteries.However,in practice,the Mg electrode still suffers from uneven stripping/deposition ...“Dendrite-free”deposition behavior of Mg^(2+)is expected to achieve planar and dense Mg growth for long-life and safe Mg batteries.However,in practice,the Mg electrode still suffers from uneven stripping/deposition in Cl-based electrolytes.Here,we reveal the low Pilling-Bedworth(P-B)ratio(0.81,the ratio of the molar volume of a metal oxide to that of the corresponding metal)of Mg metal intrinsically results in a contractive,unprotective,and inhomogeneous electrode surface,subsequently making it vulnerable in Cl-based electrolytes and inducing uneven stripping/deposition.By constructing an Al nanolayer with a high P-B ratio(1.28)to the surface of the Mg-metal electrode,we protect the electrode from corrosion,homogenize Mg stripping,and regulate planar Mg deposition.Symmetric cells with Al-Mg electrodes show a 15-fold increase in cycle life,and a Mg||Al-Cu half cell achieves an average Coulombic efficiency of 99.8%for 300 cycles at 5 mA cm^(-2)and 5 mAh cm^(-2).A long-life Al-Mg||Mo_(6)S_(8)pouch cell is also demonstrated with stable cyclability of up to 1200 cycles.This work provides a simple yet effective strategy to enhance the practical prospects of Mg batteries in terms of cycle life and safety.展开更多
基金supported by the National Key R&D Program of China(grant no.2022YFB3803500)the National Natural Science Foundation of China(grant no.52272203)the Fundamental Research Funds for the Central Universities(grant no.2021GCRC001).
文摘“Dendrite-free”deposition behavior of Mg^(2+)is expected to achieve planar and dense Mg growth for long-life and safe Mg batteries.However,in practice,the Mg electrode still suffers from uneven stripping/deposition in Cl-based electrolytes.Here,we reveal the low Pilling-Bedworth(P-B)ratio(0.81,the ratio of the molar volume of a metal oxide to that of the corresponding metal)of Mg metal intrinsically results in a contractive,unprotective,and inhomogeneous electrode surface,subsequently making it vulnerable in Cl-based electrolytes and inducing uneven stripping/deposition.By constructing an Al nanolayer with a high P-B ratio(1.28)to the surface of the Mg-metal electrode,we protect the electrode from corrosion,homogenize Mg stripping,and regulate planar Mg deposition.Symmetric cells with Al-Mg electrodes show a 15-fold increase in cycle life,and a Mg||Al-Cu half cell achieves an average Coulombic efficiency of 99.8%for 300 cycles at 5 mA cm^(-2)and 5 mAh cm^(-2).A long-life Al-Mg||Mo_(6)S_(8)pouch cell is also demonstrated with stable cyclability of up to 1200 cycles.This work provides a simple yet effective strategy to enhance the practical prospects of Mg batteries in terms of cycle life and safety.
