Conversion-alloy-type anodes have attracted considerable attention in potassium-ion batteries due to their high theoretical capacities,but the inferior stability hinders their potential applications.Generally,the fail...Conversion-alloy-type anodes have attracted considerable attention in potassium-ion batteries due to their high theoretical capacities,but the inferior stability hinders their potential applications.Generally,the failure mechanism of conversion-alloy anodes is ascribed to volume expansion or the shuttle effect,which,however,fails to adequately explain their characteristic electrochemical behavior:an initial rapid drop and then a gradual decline in capacity.Herein,by combining electrochemical characterizations with multi-scale microscopies,spectroscopy,and theoretical calculations,we systematically analyze the failure mechanism of Bi_(2)Te_(3),a typical conversion-alloy anode.The failure processes and mechanisms are identified into two stages:(1)the rapid capacity fading dominated by the shuttle effect in the first several cycles and(2)the gradual material deactivation and capacity decline due to solid-electrolyte interphase accumulation in the following cycles.Furthermore,in response to these failure mechanisms,an elaborate design of Bi_(2)Te_(3)-based electrode featuring ultrafine nanoparticles and carbon encapsulation is presented,which exhibits prominent capability in avoiding the above negative effects and substantially enhancing cycling stability.This study reveals the failure mechanism of conversion-alloy anode throughout its entire life cycle,and the gained insight may lead to targeted optimization strategies for stable high-capacity electrodes.展开更多
Iron(Fe)nanoparticles and graphite(Gr)with different masses of bismuth trisulfide(Bi_(2)S_(3))were mixed by high-energy ball milling treatment to fabricate the corresponding composite iron anodes Bi_(2)S_(3)@Fe-Gr.The...Iron(Fe)nanoparticles and graphite(Gr)with different masses of bismuth trisulfide(Bi_(2)S_(3))were mixed by high-energy ball milling treatment to fabricate the corresponding composite iron anodes Bi_(2)S_(3)@Fe-Gr.The hydrogen evolution reaction and iron passivation process on these iron electrodes were investigated in alkaline and neutral solutions.The iron electrode Bi_(2)S_(3)-3@Fe-Gr(The additional amount of Bi_(2)S_(3)was 3 mg)revealed the strongest ability to inhibit hydrogen evolution among the iron electrodes of the present investigation,while the Bi_(2)S_(3)-6@Fe-Gr electrode(The additional amount of Bi_(2)S_(3)was 6 mg)delivered significant performance in inhibiting anodic passivation.This is because the high-energy ball milling process leads to the well-dispersion of Bi_(2)S_(3)and the changes in the surface of Fe nanoparticles,thereby slowing down the passivation of the iron electrode surface.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52172240)the Natural Science Foundation of Jiangsu Province of China(BK20240591)the General Project of Education Department of Jiangsu Province(24KJB480008)。
文摘Conversion-alloy-type anodes have attracted considerable attention in potassium-ion batteries due to their high theoretical capacities,but the inferior stability hinders their potential applications.Generally,the failure mechanism of conversion-alloy anodes is ascribed to volume expansion or the shuttle effect,which,however,fails to adequately explain their characteristic electrochemical behavior:an initial rapid drop and then a gradual decline in capacity.Herein,by combining electrochemical characterizations with multi-scale microscopies,spectroscopy,and theoretical calculations,we systematically analyze the failure mechanism of Bi_(2)Te_(3),a typical conversion-alloy anode.The failure processes and mechanisms are identified into two stages:(1)the rapid capacity fading dominated by the shuttle effect in the first several cycles and(2)the gradual material deactivation and capacity decline due to solid-electrolyte interphase accumulation in the following cycles.Furthermore,in response to these failure mechanisms,an elaborate design of Bi_(2)Te_(3)-based electrode featuring ultrafine nanoparticles and carbon encapsulation is presented,which exhibits prominent capability in avoiding the above negative effects and substantially enhancing cycling stability.This study reveals the failure mechanism of conversion-alloy anode throughout its entire life cycle,and the gained insight may lead to targeted optimization strategies for stable high-capacity electrodes.
文摘Iron(Fe)nanoparticles and graphite(Gr)with different masses of bismuth trisulfide(Bi_(2)S_(3))were mixed by high-energy ball milling treatment to fabricate the corresponding composite iron anodes Bi_(2)S_(3)@Fe-Gr.The hydrogen evolution reaction and iron passivation process on these iron electrodes were investigated in alkaline and neutral solutions.The iron electrode Bi_(2)S_(3)-3@Fe-Gr(The additional amount of Bi_(2)S_(3)was 3 mg)revealed the strongest ability to inhibit hydrogen evolution among the iron electrodes of the present investigation,while the Bi_(2)S_(3)-6@Fe-Gr electrode(The additional amount of Bi_(2)S_(3)was 6 mg)delivered significant performance in inhibiting anodic passivation.This is because the high-energy ball milling process leads to the well-dispersion of Bi_(2)S_(3)and the changes in the surface of Fe nanoparticles,thereby slowing down the passivation of the iron electrode surface.
