Pore structure engineering has been acknowledged as suitable approach to creating active sites and en-hancing ion transport capabilities of hard carbon anodes.However,conventional porous carbon materials exhibit high ...Pore structure engineering has been acknowledged as suitable approach to creating active sites and en-hancing ion transport capabilities of hard carbon anodes.However,conventional porous carbon materials exhibit high BET and surface defects.Additionally,the sodium storage mechanism predominantly occurs in the slope region.This contradicts practical application requirements because the capacity of the plateau region is crucial for determining the actual capacity of batteries.In our work,we prepared a novel“core-shell”carbon framework(CNA1200).Introducingclosedporesand carboxylgroupsinto coal-basedcarbon materials to enhance its sodium storage performance.The closed pore structure dominates in the“core”structure,which is attributed to the timely removal of sodium hydroxide(NaOH)to prevent further for-mation of active carbon structure.The presence of closed pores is beneficial for increasing sodium ion storage in the low-voltage plateau region.And the“shell”structure originates from coal tar pitch,it not only uniformly connects hard carbon particles together to improve cycling stability,but is also rich in carboxyl groups to enhance the reversible sodium storage performance in slope region.CNA1200 has ex-cellent electrochemical performance,it exhibits a specific capacity of 335.2 mAh g^(−1)at a current density of 20 mA g^(−1)with ICE=51.53%.In addition,CNA1200 has outstanding cycling stability with a capac-ity retention of 91.8%even when cycling over 200 times.When CNA1200 is used as anode paired with Na_(3)V_(2)(PO_(4))_(3)cathode,it demonstrates a capacity of 109.54 mAh g^(−1)at 0.1 C and capacity retention of 94.64%at 0.5 C.This work provides valuable methods for regulating the structure of sodium-ion battery(SIBs)anode and enhances the potential for commercialization.展开更多
基金the National Natural Science Foundation of China(No.21978164,22078189 and 22105120)the Outstanding Youth Science Fund of Shaanxi Province(No.2021JC-046)and the Special Support Program for high level talents of Shaanxi Province+3 种基金the Innovation Support Program of Shaanxi Province(2021JZY-001)the Key Research and Development Program of Shaanxi Province(No.2020GY-243)the Special Research Fund of Education Department of Shaanxi(No.20JK0535)the National High-end Foreign Expert Project(No.GDW20186100428).
文摘Pore structure engineering has been acknowledged as suitable approach to creating active sites and en-hancing ion transport capabilities of hard carbon anodes.However,conventional porous carbon materials exhibit high BET and surface defects.Additionally,the sodium storage mechanism predominantly occurs in the slope region.This contradicts practical application requirements because the capacity of the plateau region is crucial for determining the actual capacity of batteries.In our work,we prepared a novel“core-shell”carbon framework(CNA1200).Introducingclosedporesand carboxylgroupsinto coal-basedcarbon materials to enhance its sodium storage performance.The closed pore structure dominates in the“core”structure,which is attributed to the timely removal of sodium hydroxide(NaOH)to prevent further for-mation of active carbon structure.The presence of closed pores is beneficial for increasing sodium ion storage in the low-voltage plateau region.And the“shell”structure originates from coal tar pitch,it not only uniformly connects hard carbon particles together to improve cycling stability,but is also rich in carboxyl groups to enhance the reversible sodium storage performance in slope region.CNA1200 has ex-cellent electrochemical performance,it exhibits a specific capacity of 335.2 mAh g^(−1)at a current density of 20 mA g^(−1)with ICE=51.53%.In addition,CNA1200 has outstanding cycling stability with a capac-ity retention of 91.8%even when cycling over 200 times.When CNA1200 is used as anode paired with Na_(3)V_(2)(PO_(4))_(3)cathode,it demonstrates a capacity of 109.54 mAh g^(−1)at 0.1 C and capacity retention of 94.64%at 0.5 C.This work provides valuable methods for regulating the structure of sodium-ion battery(SIBs)anode and enhances the potential for commercialization.
