H2TiO3 was obtained from the acid-modified adsorbent precursor Li2TiO3,which was synthesized by a solid-phase reaction between TiO2 and Li2CO3.The extraction ratio of Li＋ from Li2TiO3 was 98.86%,almost with no Ti4＋ ...H2TiO3 was obtained from the acid-modified adsorbent precursor Li2TiO3,which was synthesized by a solid-phase reaction between TiO2 and Li2CO3.The extraction ratio of Li＋ from Li2TiO3 was 98.86%,almost with no Ti4＋ extracted.The effects of lithium titanium ratio,calcining temperature and time were investigated on the synthesis of Li2TiO3.Li2TiO3,H2TiO3 and the adsorbed Li＋ adsorbent were characterized by XRD and SEM.The lithium adsorption properties were investigated by the adsorption kinetics and adsorption isotherm.The results indicate that H2TiO3 has an excellent adsorptive capacity for Li＋.Two simplified kinetic models including the pseudo-first-order and pseudo-second-order equations were selected to follow the adsorption processes.The rate constants of adsorption for these kinetic models were calculated.The results show that the adsorption process can be described by the pseudo-second-order equation,and the process is proved to be a chemical adsorption.The adsorption process that H2TiO3 adsorbs Li＋ in LiCl solution well fits the Langmuir equation with monolayer adsorption.展开更多
The rechargeable Li-CO2 battery has attracted much attention for energy storage because of the high energy density and efficient utilization of greenhouse gas. However, it＇s still suffered by low safety issue of liqu...The rechargeable Li-CO2 battery has attracted much attention for energy storage because of the high energy density and efficient utilization of greenhouse gas. However, it＇s still suffered by low safety issue of liquid electrolyte. Herein, a composite cathode consisting of CNTs and polymer electrolytes was fabricated by the insitu polymerization process for the polymer electrolyte-based solid-state Li-CO2 batteries. With the good dispersion of CNTs and polymer electrolyte, the composite cathode is covered by film-like discharge products Li2CO3.Furthermore, the Li-CO2 battery shows high reversible capacity （- 11,000 mAh·g^-1）, excellent cycle stability （1000 mAb·g^-1 for 100 cycles） under low charge potential （〈 4.5 V）, and outstanding rate performances at room temperature, which are much better than those of liquid electrolyte-based battery. Therefore, the polymer electrolyte-based Li-CO2 battery prepared by this strategy can be a promising candidate to meet the demands of high safety and high-performance energy storage devices.展开更多
Lithium carbonate （Li2CO3） is very common in various types of lithium （Li） batteries. As an insulating by-product of the oxygen reduction reaction on the cathode of a Li-air battery, it cannot be decomposed below ...Lithium carbonate （Li2CO3） is very common in various types of lithium （Li） batteries. As an insulating by-product of the oxygen reduction reaction on the cathode of a Li-air battery, it cannot be decomposed below 4.75 V （vs. Li＋/Li） during recharge and leads to a large polarization, low coulombic efficiency, and low energy conversion efficiency of the battery. On the other hand, more than 10% of the Li ions from the cathode material are consumed during chemical formation of a Li-ion battery, resulting in low coulombic efficiency and/or energy density. Consequently, lithium compensation becomes essential to realize Li-ion batteries with a higher energy density and longer cycle life. Therefore, reducing the oxidation potential of Li2CO3 is significantly important. To address these issues, we show that the addition of nanoscaled LiCoO2 can effectively lower this potential to 4.25 V. On the basis of physical characterization and electrochemical evaluation, we propose the oxidization mechanism of Li2CO3. These findings will help to decrease the polarization of Li-air batteries and provide an effective strategy for efficient Li compensation for Li-ion batteries, which can significantly improve their energy density and increase their energy conversion efficiency and cycle life.展开更多
Rechargeable lithium-carbon dioxide(Li-CO_(2))batteries have attracted much attention due to their high theoretical energy densities and capture of C0_(2).However,the electrochemical reaction mechanisms of rechargeabl...Rechargeable lithium-carbon dioxide(Li-CO_(2))batteries have attracted much attention due to their high theoretical energy densities and capture of C0_(2).However,the electrochemical reaction mechanisms of rechargeable Lo-CO_(2) batteries,particularly the decomposition mechanisms of the discharge product Li_(2)CO_(3) are still unclear,impeding their practical applications.Exploring electrochemistry of Li_(2)CO_(3) is critical for improving the performance of Li-C0_(2) batteries.Herein,in-situ environmental transmission electron microscopy(ETEM)technique was used to study electrochemistry of Li_(2)CO_(3) in Li-C0_(2) batteries during discharge and charge processes.During discharge,Li_(2)CO_(3) was nucleated and accumulated on the surface of the cathode media such as carbon nanotubes(CNTs)and Ag nanowires(Ag NWs),but it was hard to decompose during charging at room temperature.To promote the decomposition of Li2C03,the charge reactions were conducted at high temperatures,during which Li_(2)CO_(3) was decomposed to lithium with release of gases.Density functional theory(DFT)calculations revealed that the synergistic effect of temperature and biasing facilitates the decomposition of Li_(2)CO_(3).This study not only provides a fundamental understanding to the high temperature Li-C0_(2) nanobatteries,but also offers a valid technique,i.e.,discharging/charging at high temperatures,to improve the cyclability of Li-CO_(2) batteries for energy storage applications.展开更多
基金Project(2008BAB35B04) supported by the National Key Technologies R&D Program of ChinaProject(2010QZZD003) supported by Central South University Advanced Research Program,China
文摘H2TiO3 was obtained from the acid-modified adsorbent precursor Li2TiO3,which was synthesized by a solid-phase reaction between TiO2 and Li2CO3.The extraction ratio of Li＋ from Li2TiO3 was 98.86%,almost with no Ti4＋ extracted.The effects of lithium titanium ratio,calcining temperature and time were investigated on the synthesis of Li2TiO3.Li2TiO3,H2TiO3 and the adsorbed Li＋ adsorbent were characterized by XRD and SEM.The lithium adsorption properties were investigated by the adsorption kinetics and adsorption isotherm.The results indicate that H2TiO3 has an excellent adsorptive capacity for Li＋.Two simplified kinetic models including the pseudo-first-order and pseudo-second-order equations were selected to follow the adsorption processes.The rate constants of adsorption for these kinetic models were calculated.The results show that the adsorption process can be described by the pseudo-second-order equation,and the process is proved to be a chemical adsorption.The adsorption process that H2TiO3 adsorbs Li＋ in LiCl solution well fits the Langmuir equation with monolayer adsorption.
基金financially supported by the National Natural Science Foundation of China(Nos.51622202,U1507107,21503009 and 21603009)Beijing Natural Science Foundation(B)(No.KZ201610005003)+1 种基金Guangdong Science and Technology Project(No.2016B010114001)the Funding Projects for ‘‘Thousand Youth Talents Plan’’
文摘The rechargeable Li-CO2 battery has attracted much attention for energy storage because of the high energy density and efficient utilization of greenhouse gas. However, it＇s still suffered by low safety issue of liquid electrolyte. Herein, a composite cathode consisting of CNTs and polymer electrolytes was fabricated by the insitu polymerization process for the polymer electrolyte-based solid-state Li-CO2 batteries. With the good dispersion of CNTs and polymer electrolyte, the composite cathode is covered by film-like discharge products Li2CO3.Furthermore, the Li-CO2 battery shows high reversible capacity （- 11,000 mAh·g^-1）, excellent cycle stability （1000 mAb·g^-1 for 100 cycles） under low charge potential （〈 4.5 V）, and outstanding rate performances at room temperature, which are much better than those of liquid electrolyte-based battery. Therefore, the polymer electrolyte-based Li-CO2 battery prepared by this strategy can be a promising candidate to meet the demands of high safety and high-performance energy storage devices.
基金This work was supported by the National Basic Research Program of China （No. 2015CB251100） and the National Natural Science Foundation of China （No. 51372268）.
文摘Lithium carbonate （Li2CO3） is very common in various types of lithium （Li） batteries. As an insulating by-product of the oxygen reduction reaction on the cathode of a Li-air battery, it cannot be decomposed below 4.75 V （vs. Li＋/Li） during recharge and leads to a large polarization, low coulombic efficiency, and low energy conversion efficiency of the battery. On the other hand, more than 10% of the Li ions from the cathode material are consumed during chemical formation of a Li-ion battery, resulting in low coulombic efficiency and/or energy density. Consequently, lithium compensation becomes essential to realize Li-ion batteries with a higher energy density and longer cycle life. Therefore, reducing the oxidation potential of Li2CO3 is significantly important. To address these issues, we show that the addition of nanoscaled LiCoO2 can effectively lower this potential to 4.25 V. On the basis of physical characterization and electrochemical evaluation, we propose the oxidization mechanism of Li2CO3. These findings will help to decrease the polarization of Li-air batteries and provide an effective strategy for efficient Li compensation for Li-ion batteries, which can significantly improve their energy density and increase their energy conversion efficiency and cycle life.
基金supported by the the National Natural Science Foundation of China(Nos.52022088,51971245,51772262,21406191,U20A20336,and 21935009)Beijing Natural Science Foundation(No.2202046)+3 种基金Selective funding for provincial postdoctoral research projects(No.B2019003018)Fok Ying-Tong Education Foundation of China(No.171064)Natural Science Foundation of Hebei Province(Nos.B2020203037,and B2018203297)Hunan Innovation Team(No.2018RS3091).
文摘Rechargeable lithium-carbon dioxide(Li-CO_(2))batteries have attracted much attention due to their high theoretical energy densities and capture of C0_(2).However,the electrochemical reaction mechanisms of rechargeable Lo-CO_(2) batteries,particularly the decomposition mechanisms of the discharge product Li_(2)CO_(3) are still unclear,impeding their practical applications.Exploring electrochemistry of Li_(2)CO_(3) is critical for improving the performance of Li-C0_(2) batteries.Herein,in-situ environmental transmission electron microscopy(ETEM)technique was used to study electrochemistry of Li_(2)CO_(3) in Li-C0_(2) batteries during discharge and charge processes.During discharge,Li_(2)CO_(3) was nucleated and accumulated on the surface of the cathode media such as carbon nanotubes(CNTs)and Ag nanowires(Ag NWs),but it was hard to decompose during charging at room temperature.To promote the decomposition of Li2C03,the charge reactions were conducted at high temperatures,during which Li_(2)CO_(3) was decomposed to lithium with release of gases.Density functional theory(DFT)calculations revealed that the synergistic effect of temperature and biasing facilitates the decomposition of Li_(2)CO_(3).This study not only provides a fundamental understanding to the high temperature Li-C0_(2) nanobatteries,but also offers a valid technique,i.e.,discharging/charging at high temperatures,to improve the cyclability of Li-CO_(2) batteries for energy storage applications.
