Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropr...Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropriate composition modulation using heteroatoms doping and structure optimization is highly desired. A basic empirical understanding of the structure-capacity relationship is also urgent in tackling the above problems. Herein, multi-functional nitrogen (N) doped carbon micro-rods with enlarged interlayer spacing are synthesized and investigated as the anode in SIBs, showing an ultra-stable capacity of 161.5 mAh g^(−1) at 2 A g^(−1) for over 5000 cycles. Experimental investigations and first-principle calculations indicate that the enlarged interlayer spacing can facilitate Na+ intercalation and N doping can guarantee the high electric conductivity and favorable electrochemical active sites. Additionally, pyridinic N is theoretically proved to be more effective to enhance Na+ adsorption than pyrrolic N due to the lower adsorption energy and stronger binding energy with Na+. Full SIBs show a high capacity and cyclability, making the biomass-derived carbon micro-rods to be a promising anode for practical SIBs applications.展开更多
The solid-state electrolyte in a solid-state battery acts as an electrons'barrier and an ions'bridge between the two electrodes.As solid-state electrolyte does not store the mobile ions,it is necessary to achi...The solid-state electrolyte in a solid-state battery acts as an electrons'barrier and an ions'bridge between the two electrodes.As solid-state electrolyte does not store the mobile ions,it is necessary to achieve a thin solid-state electrolyte to reduce the internal resistance and enhance the energy density.In this work,a thin NASICON solid-state electrolyte,with a stoichiometry of Na_(3)Zr_(2)Si_(2)PO_(12),is fabricated by the tape-casting method and its thickness can be easily controlled by the gap between substrate and scraper.The areal-specific resistance and the flexural strength increase with the electrolyte thickness.A solid-state sodium metal battery with 86 pm thick Na_(3)Zr_(2)Si_(2)PO_(12)exhibits a reversible specific capacity of 73-78 mAh g^(-1)with a redox potential of 3.4 V at 0.2 C.This work presents the importance of electrolyte thickness to reduce internal resistance and achieve a high energy density for sodium batteries.展开更多
Generation of large strains upon Na^(+) intercalation is one of the prime concerns of the mechanical degradation of Prussian blue(PB)and its analogs.Structural construction from the atomic level is imperative to maint...Generation of large strains upon Na^(+) intercalation is one of the prime concerns of the mechanical degradation of Prussian blue(PB)and its analogs.Structural construction from the atomic level is imperative to maintain structural stability and ameliorate the long-term stability of PB.Herein,an inter nickel hexacyanoferrate(NNiFCN)is successfully introduced at the out layer of iron hexacyanoferrate(NFFCN)through ion exchange to improve structural stability through compressive stress locking by forming NNiFCN shell.Furthermore,the kinetics of sodium ion diffusion is enhanced through the built-in electric pathway.The electrochemical performance is therefore significantly improved with a remarkable long-term cycling stability over 3,000 cycles at 500 mA·g^(–1) in the full sodium-ion batteries(SIBs)with a maximum energy density of 91.94 Wh·g^(–1),indicating that the core-shell structured NNiFCN/NFFCN could be the low-cost and high-performance cathode for full SIBs in large-scale EES applications.展开更多
基金J.G.Sun appreciates the scholarship support from China Scholarship Council(CSC)under grant No.201706050153.
文摘Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropriate composition modulation using heteroatoms doping and structure optimization is highly desired. A basic empirical understanding of the structure-capacity relationship is also urgent in tackling the above problems. Herein, multi-functional nitrogen (N) doped carbon micro-rods with enlarged interlayer spacing are synthesized and investigated as the anode in SIBs, showing an ultra-stable capacity of 161.5 mAh g^(−1) at 2 A g^(−1) for over 5000 cycles. Experimental investigations and first-principle calculations indicate that the enlarged interlayer spacing can facilitate Na+ intercalation and N doping can guarantee the high electric conductivity and favorable electrochemical active sites. Additionally, pyridinic N is theoretically proved to be more effective to enhance Na+ adsorption than pyrrolic N due to the lower adsorption energy and stronger binding energy with Na+. Full SIBs show a high capacity and cyclability, making the biomass-derived carbon micro-rods to be a promising anode for practical SIBs applications.
基金Agency for Science,Technology and Research for its funding(U21-M1-019AR).
文摘The solid-state electrolyte in a solid-state battery acts as an electrons'barrier and an ions'bridge between the two electrodes.As solid-state electrolyte does not store the mobile ions,it is necessary to achieve a thin solid-state electrolyte to reduce the internal resistance and enhance the energy density.In this work,a thin NASICON solid-state electrolyte,with a stoichiometry of Na_(3)Zr_(2)Si_(2)PO_(12),is fabricated by the tape-casting method and its thickness can be easily controlled by the gap between substrate and scraper.The areal-specific resistance and the flexural strength increase with the electrolyte thickness.A solid-state sodium metal battery with 86 pm thick Na_(3)Zr_(2)Si_(2)PO_(12)exhibits a reversible specific capacity of 73-78 mAh g^(-1)with a redox potential of 3.4 V at 0.2 C.This work presents the importance of electrolyte thickness to reduce internal resistance and achieve a high energy density for sodium batteries.
基金J.G.S.wants to thanks China Scholarship Council(CSC)for the scholarship support(No.201706050153)。
文摘Generation of large strains upon Na^(+) intercalation is one of the prime concerns of the mechanical degradation of Prussian blue(PB)and its analogs.Structural construction from the atomic level is imperative to maintain structural stability and ameliorate the long-term stability of PB.Herein,an inter nickel hexacyanoferrate(NNiFCN)is successfully introduced at the out layer of iron hexacyanoferrate(NFFCN)through ion exchange to improve structural stability through compressive stress locking by forming NNiFCN shell.Furthermore,the kinetics of sodium ion diffusion is enhanced through the built-in electric pathway.The electrochemical performance is therefore significantly improved with a remarkable long-term cycling stability over 3,000 cycles at 500 mA·g^(–1) in the full sodium-ion batteries(SIBs)with a maximum energy density of 91.94 Wh·g^(–1),indicating that the core-shell structured NNiFCN/NFFCN could be the low-cost and high-performance cathode for full SIBs in large-scale EES applications.
