Iron hexacyanoferrate(FeHCF)is a promising cathode material for sodium-ion batteries.However,FeHCF always suffers from a poor cycling stability,which is closely related to the abundant vacancy defects in its framework...Iron hexacyanoferrate(FeHCF)is a promising cathode material for sodium-ion batteries.However,FeHCF always suffers from a poor cycling stability,which is closely related to the abundant vacancy defects in its framework.Herein,post-synthetic and in-situ vacancy repairing strategies are proposed for the synthesis of highquality FeHCF in a highly concentrated Na_(4)Fe(CN)_(6) solution.Both the post-synthetic and in-situ vacancy repaired FeHCF products(FeHCF-P and FeHCF-I)show the significant decrease in the number of vacancy defects and the reinforced structure,which can suppress the side reactions and activate the capacity from low-spin Fe in FeHCF.In particular,FeHCF-P delivers a reversible discharge capacity of 131 mAh g^(−1) at 1 C and remains 109 mAh g^(−1) after 500 cycles,with a capacity retention of 83%.FeHCF-I can deliver a high discharge capacity of 158.5 mAh g^(−1) at 1 C.Even at 10 C,the FeHCF-I electrode still maintains a discharge specific capacity of 103 mAh g^(−1) and retains 75% after 800 cycles.This work provides a new vacancy repairing strategy for the solution synthesis of high-quality FeHCF.展开更多
基金supported by the projects of the National Key R&D Program of China(2016YFB0100302)the National Natural Science Foundation of China(Grant No.60306011).
文摘Iron hexacyanoferrate(FeHCF)is a promising cathode material for sodium-ion batteries.However,FeHCF always suffers from a poor cycling stability,which is closely related to the abundant vacancy defects in its framework.Herein,post-synthetic and in-situ vacancy repairing strategies are proposed for the synthesis of highquality FeHCF in a highly concentrated Na_(4)Fe(CN)_(6) solution.Both the post-synthetic and in-situ vacancy repaired FeHCF products(FeHCF-P and FeHCF-I)show the significant decrease in the number of vacancy defects and the reinforced structure,which can suppress the side reactions and activate the capacity from low-spin Fe in FeHCF.In particular,FeHCF-P delivers a reversible discharge capacity of 131 mAh g^(−1) at 1 C and remains 109 mAh g^(−1) after 500 cycles,with a capacity retention of 83%.FeHCF-I can deliver a high discharge capacity of 158.5 mAh g^(−1) at 1 C.Even at 10 C,the FeHCF-I electrode still maintains a discharge specific capacity of 103 mAh g^(−1) and retains 75% after 800 cycles.This work provides a new vacancy repairing strategy for the solution synthesis of high-quality FeHCF.
