Building anion-derived solid electrolyte interphase(SEI)with enriched LiF is considered the most promising strategy to address inferior safety features and poor cyclability of lithium-metal batteries(LMBs).Herein,we d...Building anion-derived solid electrolyte interphase(SEI)with enriched LiF is considered the most promising strategy to address inferior safety features and poor cyclability of lithium-metal batteries(LMBs).Herein,we discover that,instead of direct electron transfer from surface polar groups to bis(trifluoromethanesulfonyl)imide(TFSI-)for inducing a LiF-rich SEI,the dipole-induced fluorinated-anion decomposition reaction begins with the adsorption of Li ions and is highly dependent on their mobility on the polar surface.To demonstrate this,a single-layer graphdiyne on MXene(sGDY@MXene)heterostructure has been successfully fabricated and integrated into polypropylene separators.It is found that the adsorbed Li ions connect electron-donating sGDY@MXene to TFSI-,facilitating interfacial charge transfer for TFSI-decomposition.However,this does not capture the entire picture.The sGDY@MXene also renders the adsorbed Li ions with high mobility,enabling them to reach optimal reaction sites and expedite their coordination processes with O on O=S=O and F on the broken–CF_3~-,facilitating bond cleavage.In contrast,immobilized Li ions on the more lithiophilic pristine MXene retard these cleavage processes.Consequently,the decomposition reaction is accelerated on sGDY@MXene.This work highlights the dedicate balance between lithiophilicity and Li-ion mobility in effectively promoting a LiF-rich SEI for the long-term stability of LMBs.展开更多
Supercapacitors(SCs)stand out among various energy storage devices owing to their high power density and long-term cyc-ling stability.As new two-dimensional material,MXenes have become a research hotspot in recent yea...Supercapacitors(SCs)stand out among various energy storage devices owing to their high power density and long-term cyc-ling stability.As new two-dimensional material,MXenes have become a research hotspot in recent years owing to their unique structure and rich surface functional groups.Compared with other materials,MXenes are more promising for SCs owing to their tunable precurs-ors,structural stability,and excellent electrical conductivity.However,the rate performance and electrochemical reaction activity of MXene materials are poor,and stacking severely limits their application.Therefore,various modification strategies are employed to im-prove the electrochemical performance of MXene materials.As the modification strategy of MXene electrode materials often involves in-creasing the number of ion transport channels to expose more active sites,the packing density is also affected to different degrees.There-fore,achieving a balance between high volumetric capacitance and rapid ion transport has become a key issue for the application of MXene-based SCs in wearable devices and microdevices.In this paper,the latest progress in the preparation methods and modification strategies of MXenes in recent years is reviewed with the aim of achieving both high volumetric capacitance and high ion transport for ex-panding the application of MXene-based SCs in microdevices and wearable devices.展开更多
MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in supercapacitors.However,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene...MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in supercapacitors.However,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene until now,while the bimetallic and multimetallic MXene have received comparatively less attention.In this work,we demonstrate that the electronic structure of the Mo_(2)TiC_(2)T_(x) MXene could be regulated by fine-tuning the content of doped Nb atoms.The enhanced electron cloud density of surface–O termination and the electron spin of the Mo atoms in the Mo_(2)TiC_(2)T_(x) MXene,leads to the boost of electric double-layer capacitor(EDLC)and improvement of pseudocapacitance.As a consequence,the electrochemical performance of Nb-doped Mo_(2)TiC_(2)T_(x) MXene(Nb-0.3-MXene)demonstrates a capacitance of 398 F·cm^(−3),roughly doubling that of the pristine Mo_(2)TiC_(2)T_(x) MXene electrode at 197 F·cm^(−3) in the 3 M H_(2)SO_(4) electrolyte.At the same time,the Nb-0.3-MXene could even maintain a capacitance of 82.75% at 200 mV·s−1,with high cyclic stability for 19,000 cycles at 10 A·g−1.Additionally,Nb-0.3-MXene-based hybrid supercapacitors deliver a remarkable volumetric energy density of 48.1 W·h·L^(−1)at 230.7 W·L^(−1),and 34.4 W·h·L^(−1)at a high power density of 82.6 kW·L^(−1).There exists a balance between the volumetric capacitance and rate performance with different ratios of Nb atoms in the Nb-doped MXene due to the strong interaction between the Nb-doped MXene and the intercalated protons.Therefore,optimizing the electronic structure of MXene through heteroatom doping is of great potential for enhanced supercapacitor performance.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.52272242,52174387,and 52403339)Key Research and Development Program of Henan Province(No.231111240600)。
文摘Building anion-derived solid electrolyte interphase(SEI)with enriched LiF is considered the most promising strategy to address inferior safety features and poor cyclability of lithium-metal batteries(LMBs).Herein,we discover that,instead of direct electron transfer from surface polar groups to bis(trifluoromethanesulfonyl)imide(TFSI-)for inducing a LiF-rich SEI,the dipole-induced fluorinated-anion decomposition reaction begins with the adsorption of Li ions and is highly dependent on their mobility on the polar surface.To demonstrate this,a single-layer graphdiyne on MXene(sGDY@MXene)heterostructure has been successfully fabricated and integrated into polypropylene separators.It is found that the adsorbed Li ions connect electron-donating sGDY@MXene to TFSI-,facilitating interfacial charge transfer for TFSI-decomposition.However,this does not capture the entire picture.The sGDY@MXene also renders the adsorbed Li ions with high mobility,enabling them to reach optimal reaction sites and expedite their coordination processes with O on O=S=O and F on the broken–CF_3~-,facilitating bond cleavage.In contrast,immobilized Li ions on the more lithiophilic pristine MXene retard these cleavage processes.Consequently,the decomposition reaction is accelerated on sGDY@MXene.This work highlights the dedicate balance between lithiophilicity and Li-ion mobility in effectively promoting a LiF-rich SEI for the long-term stability of LMBs.
基金supported by the National Natural Science Foundation of China(No.52272242)the Provisional Key Research and Development Program of Henan Province,China(No.231111240600)+1 种基金the Natural Science Foundation of Henan Province,China(No.242300421428)the Start-up Funding for Scientific Research of Zhengzhou University,China(No.32310221).
文摘Supercapacitors(SCs)stand out among various energy storage devices owing to their high power density and long-term cyc-ling stability.As new two-dimensional material,MXenes have become a research hotspot in recent years owing to their unique structure and rich surface functional groups.Compared with other materials,MXenes are more promising for SCs owing to their tunable precurs-ors,structural stability,and excellent electrical conductivity.However,the rate performance and electrochemical reaction activity of MXene materials are poor,and stacking severely limits their application.Therefore,various modification strategies are employed to im-prove the electrochemical performance of MXene materials.As the modification strategy of MXene electrode materials often involves in-creasing the number of ion transport channels to expose more active sites,the packing density is also affected to different degrees.There-fore,achieving a balance between high volumetric capacitance and rapid ion transport has become a key issue for the application of MXene-based SCs in wearable devices and microdevices.In this paper,the latest progress in the preparation methods and modification strategies of MXenes in recent years is reviewed with the aim of achieving both high volumetric capacitance and high ion transport for ex-panding the application of MXene-based SCs in microdevices and wearable devices.
基金supported by the National Natural Science Foundation of China(No.52272242)the Provisional Key Research and Development Program of Henan Province(No.231111240600)+1 种基金the Natural Science Foundation of Henan Province(No.242300421428)the Start-up Funding for Scientific Research of Zhengzhou University(No.32310221).
文摘MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in supercapacitors.However,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene until now,while the bimetallic and multimetallic MXene have received comparatively less attention.In this work,we demonstrate that the electronic structure of the Mo_(2)TiC_(2)T_(x) MXene could be regulated by fine-tuning the content of doped Nb atoms.The enhanced electron cloud density of surface–O termination and the electron spin of the Mo atoms in the Mo_(2)TiC_(2)T_(x) MXene,leads to the boost of electric double-layer capacitor(EDLC)and improvement of pseudocapacitance.As a consequence,the electrochemical performance of Nb-doped Mo_(2)TiC_(2)T_(x) MXene(Nb-0.3-MXene)demonstrates a capacitance of 398 F·cm^(−3),roughly doubling that of the pristine Mo_(2)TiC_(2)T_(x) MXene electrode at 197 F·cm^(−3) in the 3 M H_(2)SO_(4) electrolyte.At the same time,the Nb-0.3-MXene could even maintain a capacitance of 82.75% at 200 mV·s−1,with high cyclic stability for 19,000 cycles at 10 A·g−1.Additionally,Nb-0.3-MXene-based hybrid supercapacitors deliver a remarkable volumetric energy density of 48.1 W·h·L^(−1)at 230.7 W·L^(−1),and 34.4 W·h·L^(−1)at a high power density of 82.6 kW·L^(−1).There exists a balance between the volumetric capacitance and rate performance with different ratios of Nb atoms in the Nb-doped MXene due to the strong interaction between the Nb-doped MXene and the intercalated protons.Therefore,optimizing the electronic structure of MXene through heteroatom doping is of great potential for enhanced supercapacitor performance.
