Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode,thereby elevating the cycle performance as well as open-circuit voltage for full m...Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode,thereby elevating the cycle performance as well as open-circuit voltage for full metal ion capacitors(MICs).However,suffered from massive-dosage abuse,exorbitant decomposition potential,and side effects of decomposition residue,the wide application of sacrificial approach was restricted.Herein,assisted with density functional theory calculations,strongly coupled interface(M-O-C,M=Li/Na/K)and electron donating group have been put forward to regulate the band gap and highest occupied molecular orbital level of metal oxalate(M_(2)C_(2)O_(4)),reducing polarization phenomenon and Gibbs free energy required for decomposition,which eventually decrease the practical decomposition potential from 4.50 to 3.95 V.Remarkably,full sodium ion capacitors constituted of commercial materials(activated carbon//hard carbon)could deliver a prominent energy density of 118.2 Wh kg^(−1)as well as excellent cycle stability under an ultra-low dosage pre-sodiation reagent of 15-30 wt%(far less than currently 100 wt%).Noteworthily,decomposition mechanism of sacrificial compound and the relative influence on the system of MICs after pre-metallation were initially revealed by in situ differential electrochemical mass spectrometry,offering in-depth insights for comprehending the function of cathode additives.In addition,this breakthrough has been successfully utilized in high performance lithium/potassium ion capacitors with Li_(2)C_(2)O_(4)/K_(2)C_(2)O_(4) as pre-metallation reagent,which will convincingly promote the commercialization of MICs.展开更多
基金supported by the National Natural Science Foundation of China(52004338)the Hunan Provincial Natural Science Foundation of China(2020JJ5696)+2 种基金the Science,and Technology Innovation Program of Hunan Province(2020RC4005,2019RS1004)Guangdong Provincial Department of Natural Resources(2020-011)supported in part by the High Performance Computing Center of Central South University.
文摘Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode,thereby elevating the cycle performance as well as open-circuit voltage for full metal ion capacitors(MICs).However,suffered from massive-dosage abuse,exorbitant decomposition potential,and side effects of decomposition residue,the wide application of sacrificial approach was restricted.Herein,assisted with density functional theory calculations,strongly coupled interface(M-O-C,M=Li/Na/K)and electron donating group have been put forward to regulate the band gap and highest occupied molecular orbital level of metal oxalate(M_(2)C_(2)O_(4)),reducing polarization phenomenon and Gibbs free energy required for decomposition,which eventually decrease the practical decomposition potential from 4.50 to 3.95 V.Remarkably,full sodium ion capacitors constituted of commercial materials(activated carbon//hard carbon)could deliver a prominent energy density of 118.2 Wh kg^(−1)as well as excellent cycle stability under an ultra-low dosage pre-sodiation reagent of 15-30 wt%(far less than currently 100 wt%).Noteworthily,decomposition mechanism of sacrificial compound and the relative influence on the system of MICs after pre-metallation were initially revealed by in situ differential electrochemical mass spectrometry,offering in-depth insights for comprehending the function of cathode additives.In addition,this breakthrough has been successfully utilized in high performance lithium/potassium ion capacitors with Li_(2)C_(2)O_(4)/K_(2)C_(2)O_(4) as pre-metallation reagent,which will convincingly promote the commercialization of MICs.
