The ether electrolytes usually outperform ester electrolytes by evaluating sodium-ion batteries(SIBs)rate performance,which is a near-unanimous conclusion of previous studies based on an essential configuration of the...The ether electrolytes usually outperform ester electrolytes by evaluating sodium-ion batteries(SIBs)rate performance,which is a near-unanimous conclusion of previous studies based on an essential configuration of the half-cell test.However,here we find that contrary to consensus,the ester electrolyte shows better Na storage capability than the ether electrolyte in full cells.An in-depth analysis of three-electrode,symmetric cell,and in situ XRD tests indicates that traditional half-cell test results are unreliable due to interference from Na electrodes.In particular,Na electrodes show a huge stability difference in ester and ether electrolytes,and ester electrolytes suffer more severe interference than ether electrolytes,resulting in the belief that esters are far inferior to ether electrolytes.More seriously,the more accurate three-electrode test would also suffer from Na electrode interference.Thus,a“corrected half-cell test”protocol is developed to shield the Na electrode interference,revealing the very close super rate capability of hard carbon in ester and ether electrolytes.This work breaks the inherent perception that the kinetic properties of ester electrolytes are inferior to ethers in sodium-ion batteries,reveals the pitfalls of half-cell tests,and proposes a new test protocol for reliable results,greatly accelerating the commercialization of sodium-ion batteries.展开更多
Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method.The structural change and the effect on the electrochemical properties are systematic...Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method.The structural change and the effect on the electrochemical properties are systematically investigated. Nitrogen-doped lignin-based carbon microspheres represent well-developed spherical morphology with many active sites, ultramicroporous(< 0.7 nm) structure, and large interlayer spacing. Consistent with the obtained physical structures and properties, the nitrogen-doped carbon microspheres exhibit fast sodium ion adsorption/intercalation kinetic process and excellent electrochemical performance. For example, a reversible specific capacity of 374 m Ah g^(-1) at 25 m A g^(-1) with high initial coulombic efficiency of 85% and high capacitance retention of 90% after 300 cycles at 100 m A g^(-1) and stable charge/discharge behavior at different current density is obtained. The additional defects and abundant ultramicroporous structure can enhance sloping capacity, and large interlayer spacing is considered to be the reason for improving plateau capacity.展开更多
Due to its low cost and easy availability, the pitch is considered a promising precursor for soft carbon anodes. However, pitch-derived soft carbon shows a high graphitization degree and small interlayer spacing, resu...Due to its low cost and easy availability, the pitch is considered a promising precursor for soft carbon anodes. However, pitch-derived soft carbon shows a high graphitization degree and small interlayer spacing, resulting in its much lower sodium storage performance than hard carbon. We propose a novel preoxidation strategy to introduce additional oxygen atoms into the low-cost soft carbon precursor pitch to fabricate a defect-rich and large-interlayer spacing hard carbon anode(HPP-1100). Compared with the direct pyrolysis of pitch carbon, the sodium storage capacity of HPP-1100 is significantly improved from 120.3 m Ah/g to 306.7 m Ah/g, with an excellent rate and cycling capability(116.5 m Ah/g at 10 C). Moreover, when assorted with an O_(3)-Na(NiFeMn)1/3O_(2)cathode, the full cell delivers a high reversible capacity of 274.0 m Ah/g at 0.1 C with superb cycle life. This work provides a new solution for realizing the application of low-cost pitch anodes in Na-ion batteries.展开更多
Aqueous electrolytes offer superior prospects for advanced energy storage.“Water-in-salt”(WIS)electrolytes exhibit a wide electrochemical stability window(ESW),but their low conductivity,high viscosity,and precipita...Aqueous electrolytes offer superior prospects for advanced energy storage.“Water-in-salt”(WIS)electrolytes exhibit a wide electrochemical stability window(ESW),but their low conductivity,high viscosity,and precipitation at low temperatures restrict their application.Herein,we report a novel localized“water-in-pyrrolidinium chloride”electrolyte(LWIP;1 mol/L,N-propyl-N-methylpyrrolidinium chloride/(water and N,Ndimethylformamide,1:4 by molality))enabling high-voltage,low-temperature supercapacitors(SCs).The greatly improved ESW(3.451 V)is mainly attributed to the strong solvation between Cl-and water molecules,which broadens the negative stability.This water-binding mechanism is very different from that of a WIS electrolyte based on alkali metal salt.SCs using LWIP electrolytes not only yield a high operating voltage of 2.4 V and excellent capacity retention(82.8%after 15,000 cycles at 5 A g^(-1))but also operate stably at-20℃.This work provides new approaches for the design and preparation of novel electrolytes.展开更多
基金supported by the National Natural Science Foundation of China(22179094)the Tianjin Research Program of Application Foundation and Advanced Technology of China(15ZCZDGX00270)
文摘The ether electrolytes usually outperform ester electrolytes by evaluating sodium-ion batteries(SIBs)rate performance,which is a near-unanimous conclusion of previous studies based on an essential configuration of the half-cell test.However,here we find that contrary to consensus,the ester electrolyte shows better Na storage capability than the ether electrolyte in full cells.An in-depth analysis of three-electrode,symmetric cell,and in situ XRD tests indicates that traditional half-cell test results are unreliable due to interference from Na electrodes.In particular,Na electrodes show a huge stability difference in ester and ether electrolytes,and ester electrolytes suffer more severe interference than ether electrolytes,resulting in the belief that esters are far inferior to ether electrolytes.More seriously,the more accurate three-electrode test would also suffer from Na electrode interference.Thus,a“corrected half-cell test”protocol is developed to shield the Na electrode interference,revealing the very close super rate capability of hard carbon in ester and ether electrolytes.This work breaks the inherent perception that the kinetic properties of ester electrolytes are inferior to ethers in sodium-ion batteries,reveals the pitfalls of half-cell tests,and proposes a new test protocol for reliable results,greatly accelerating the commercialization of sodium-ion batteries.
基金the support of the National Natural Science Foundation of China(51603147)Tianjin application foundation and advanced technology research plan project(15ZCZDGX00270 and 14RCHZGX00859)。
文摘Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method.The structural change and the effect on the electrochemical properties are systematically investigated. Nitrogen-doped lignin-based carbon microspheres represent well-developed spherical morphology with many active sites, ultramicroporous(< 0.7 nm) structure, and large interlayer spacing. Consistent with the obtained physical structures and properties, the nitrogen-doped carbon microspheres exhibit fast sodium ion adsorption/intercalation kinetic process and excellent electrochemical performance. For example, a reversible specific capacity of 374 m Ah g^(-1) at 25 m A g^(-1) with high initial coulombic efficiency of 85% and high capacitance retention of 90% after 300 cycles at 100 m A g^(-1) and stable charge/discharge behavior at different current density is obtained. The additional defects and abundant ultramicroporous structure can enhance sloping capacity, and large interlayer spacing is considered to be the reason for improving plateau capacity.
基金supported by the National Natural Science Foundation of China (No. 22179094)。
文摘Due to its low cost and easy availability, the pitch is considered a promising precursor for soft carbon anodes. However, pitch-derived soft carbon shows a high graphitization degree and small interlayer spacing, resulting in its much lower sodium storage performance than hard carbon. We propose a novel preoxidation strategy to introduce additional oxygen atoms into the low-cost soft carbon precursor pitch to fabricate a defect-rich and large-interlayer spacing hard carbon anode(HPP-1100). Compared with the direct pyrolysis of pitch carbon, the sodium storage capacity of HPP-1100 is significantly improved from 120.3 m Ah/g to 306.7 m Ah/g, with an excellent rate and cycling capability(116.5 m Ah/g at 10 C). Moreover, when assorted with an O_(3)-Na(NiFeMn)1/3O_(2)cathode, the full cell delivers a high reversible capacity of 274.0 m Ah/g at 0.1 C with superb cycle life. This work provides a new solution for realizing the application of low-cost pitch anodes in Na-ion batteries.
基金funding provided by Cangzhou Institute of Tiangong University (Grant No.TGCYY-Z-0202)the National Natural Science Foundation of China (22179094)Tianjin Application Foundation and Advanced Technology Research Plan Project (15ZCZDGX00270,14RCHZGX00859).
文摘Aqueous electrolytes offer superior prospects for advanced energy storage.“Water-in-salt”(WIS)electrolytes exhibit a wide electrochemical stability window(ESW),but their low conductivity,high viscosity,and precipitation at low temperatures restrict their application.Herein,we report a novel localized“water-in-pyrrolidinium chloride”electrolyte(LWIP;1 mol/L,N-propyl-N-methylpyrrolidinium chloride/(water and N,Ndimethylformamide,1:4 by molality))enabling high-voltage,low-temperature supercapacitors(SCs).The greatly improved ESW(3.451 V)is mainly attributed to the strong solvation between Cl-and water molecules,which broadens the negative stability.This water-binding mechanism is very different from that of a WIS electrolyte based on alkali metal salt.SCs using LWIP electrolytes not only yield a high operating voltage of 2.4 V and excellent capacity retention(82.8%after 15,000 cycles at 5 A g^(-1))but also operate stably at-20℃.This work provides new approaches for the design and preparation of novel electrolytes.
