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Tianshou Zhao - One of the best experts on this subject based on the ideXlab platform.

  • effects of moist air on the cycling performance of non aqueous lithium air batteries
    Applied Energy, 2016
    Co-Authors: Wei Shyy, Tianshou Zhao, Ruihan Zhang
    Abstract:

    Most non-aqueous Lithium-Air batteries reported in the literature are limited to operating with pure oxygen. To practically operate the Battery in ambient air, understanding how the Battery’s performance varies with humidity of moist air is essential. Here we study the effects of moist air on the cycling performance through operating a non-aqueous Lithium-Air Battery with a stable anode and a nano-structured RuO2/NiO cathode at various relative humidities. Results show that in the dry air, the discharge and charge terminal voltages are around 2.51 and 4.12V, respectively, but change to 2.79 and 3.87V when the relative humidity reaches 84%. The energy efficiencies corresponding to the dry air and the relative humidity of 84% are 66.2% and 73.8%, respectively. The improved performance is found to be mainly due to the increased fraction of LiOH among the discharge products at high relative humidities. The discharge voltage for the formation of LiOH is higher than that for the formation of Li2O2, while the charge voltage for the decomposition of LiOH is lower than that for the decomposition of Li2O2. The results suggest that to enable a non-aqueous Lithium-Air Battery to operate in moist air, in addition to protecting the lithium anode from water, designing a cathode with electrocatalytic activities for the decomposition of both Li2O2 and LiOH is required.

  • a nano structured ruo2 nio cathode enables the operation of non aqueous lithium air batteries in ambient air
    Energy and Environmental Science, 2016
    Co-Authors: Wei Shyy, Tianshou Zhao
    Abstract:

    We report a cathode composed of RuO2 nanoparticle-decorated NiO nanosheets for a non-aqueous lithium–air Battery. Unlike most of the previously reported non-aqueous lithium–air batteries that are operated with pure oxygen only, we demonstrate that the present cathode enables the Battery to be truly operated in ambient air at 500 mA h g−1 for 200 cycles (800 h), with stable coulombic efficiency (100%) and high energy efficiency (∼75%). The stellar performance is attributed to the favorable combination of RuO2 nanoparticles and NiO nanosheets, which not only catalyzes the oxygen reduction and evolution reactions, but also promotes the decomposition of the side products, including lithium hydroxide and carbonate formed from water and carbon dioxide in the air during discharge.

  • A nano-structured RuO2/NiO cathode enables the operation of non-aqueous lithium–air batteries in ambient air
    Energy & Environmental Science, 2016
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei, Xingbao Zhu
    Abstract:

    We report a cathode composed of RuO2 nanoparticle-decorated NiO nanosheets for a non-aqueous lithium–air Battery. Unlike most of the previously reported non-aqueous lithium–air batteries that are operated with pure oxygen only, we demonstrate that the present cathode enables the Battery to be truly operated in ambient air at 500 mA h g−1 for 200 cycles (800 h), with stable coulombic efficiency (100%) and high energy efficiency (∼75%). The stellar performance is attributed to the favorable combination of RuO2 nanoparticles and NiO nanosheets, which not only catalyzes the oxygen reduction and evolution reactions, but also promotes the decomposition of the side products, including lithium hydroxide and carbonate formed from water and carbon dioxide in the air during discharge.

  • A high-rate and long cycle life solid-state lithium–air Battery
    Energy & Environmental Science, 2015
    Co-Authors: Xingbao Zhu, Tianshou Zhao, Zhaohuan Wei, Peng Tan
    Abstract:

    Lithium–air batteries are currently limited to being operated under pure oxygen rather than ambient air, primarily due to the discharge product, lithium peroxide, reacting with water and carbon dioxide in ambient air to produce lithium carbonate, which renders the Battery irreversible. A solution to this debilitating problem is to install an oxygen selective membrane that only allows oxygen to enter the Battery. While theoretically sound, this method causes a significant decrease in the oxygen transfer rate due to a limited oxygen permeation area of the planar membrane and an increase in the oxygen transport distance from the membrane to the reaction sites. In this work, we create a novel solid-state lithium–air Battery having a porous LATP cathode, designed using silicone-oil film coated pores that block water vapor and carbon dioxide from reaching reaction sites, but allow a high rate of oxygen transfer owing to an increase in the specific area of the films and a reduced oxygen transfer resistance. This Battery can operate in ambient air at 5000 mA h gcarbon−1 for 50 cycles (125 days). Moreover, the charge/discharge rate reaches as high as 2.0 mA cm−2, a value which is about 40 times higher than that of conventional lithium–air batteries having an oxygen selective membrane external to the cathode.

  • Discharge product morphology versus operating temperature in non-aqueous Lithium-Air batteries
    Journal of Power Sources, 2015
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei
    Abstract:

    Abstract During the discharge process of non-aqueous Lithium-Air batteries, a solid product, Li 2 O 2 , forms in the pores of the porous cathode, and eventually causes the discharge process to cease. During the charge process, solid Li 2 O 2 needs to be electrochemically oxidized. The morphology of the discharge product is, therefore, critically related to the capacity and reversibility of the Battery. In this work, we experimentally show that for a given design of the cathode, the shape of the discharge product Li 2 O 2 at a given discharge current density remains almost unchanged with a change in the operating temperature, but the size decreases with an increase in the temperature. We also demonstrate that the product shape varies with the discharge current density at a given temperature. The practical implication of these findings is that the capacity, charge voltage, and cyclability of a given non-aqueous Lithium-Air Battery are affected by the operating temperature.

Peng Tan - One of the best experts on this subject based on the ideXlab platform.

  • A nano-structured RuO2/NiO cathode enables the operation of non-aqueous lithium–air batteries in ambient air
    Energy & Environmental Science, 2016
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei, Xingbao Zhu
    Abstract:

    We report a cathode composed of RuO2 nanoparticle-decorated NiO nanosheets for a non-aqueous lithium–air Battery. Unlike most of the previously reported non-aqueous lithium–air batteries that are operated with pure oxygen only, we demonstrate that the present cathode enables the Battery to be truly operated in ambient air at 500 mA h g−1 for 200 cycles (800 h), with stable coulombic efficiency (100%) and high energy efficiency (∼75%). The stellar performance is attributed to the favorable combination of RuO2 nanoparticles and NiO nanosheets, which not only catalyzes the oxygen reduction and evolution reactions, but also promotes the decomposition of the side products, including lithium hydroxide and carbonate formed from water and carbon dioxide in the air during discharge.

  • A high-rate and long cycle life solid-state lithium–air Battery
    Energy & Environmental Science, 2015
    Co-Authors: Xingbao Zhu, Tianshou Zhao, Zhaohuan Wei, Peng Tan
    Abstract:

    Lithium–air batteries are currently limited to being operated under pure oxygen rather than ambient air, primarily due to the discharge product, lithium peroxide, reacting with water and carbon dioxide in ambient air to produce lithium carbonate, which renders the Battery irreversible. A solution to this debilitating problem is to install an oxygen selective membrane that only allows oxygen to enter the Battery. While theoretically sound, this method causes a significant decrease in the oxygen transfer rate due to a limited oxygen permeation area of the planar membrane and an increase in the oxygen transport distance from the membrane to the reaction sites. In this work, we create a novel solid-state lithium–air Battery having a porous LATP cathode, designed using silicone-oil film coated pores that block water vapor and carbon dioxide from reaching reaction sites, but allow a high rate of oxygen transfer owing to an increase in the specific area of the films and a reduced oxygen transfer resistance. This Battery can operate in ambient air at 5000 mA h gcarbon−1 for 50 cycles (125 days). Moreover, the charge/discharge rate reaches as high as 2.0 mA cm−2, a value which is about 40 times higher than that of conventional lithium–air batteries having an oxygen selective membrane external to the cathode.

  • Discharge product morphology versus operating temperature in non-aqueous Lithium-Air batteries
    Journal of Power Sources, 2015
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei
    Abstract:

    Abstract During the discharge process of non-aqueous Lithium-Air batteries, a solid product, Li 2 O 2 , forms in the pores of the porous cathode, and eventually causes the discharge process to cease. During the charge process, solid Li 2 O 2 needs to be electrochemically oxidized. The morphology of the discharge product is, therefore, critically related to the capacity and reversibility of the Battery. In this work, we experimentally show that for a given design of the cathode, the shape of the discharge product Li 2 O 2 at a given discharge current density remains almost unchanged with a change in the operating temperature, but the size decreases with an increase in the temperature. We also demonstrate that the product shape varies with the discharge current density at a given temperature. The practical implication of these findings is that the capacity, charge voltage, and cyclability of a given non-aqueous Lithium-Air Battery are affected by the operating temperature.

  • A gradient porous cathode for non-aqueous Lithium-Air batteries leading to a high capacity
    Electrochemistry Communications, 2014
    Co-Authors: Peng Tan, Zhaohuan Wei, Wei Shyy, Tianshou Zhao
    Abstract:

    Abstract In conventional porous cathodes of non-aqueous Lithium-Air batteries, the higher discharge reaction rate in the oxygen richer region will result in a gradient distribution of the solid product, Li 2 O 2 , decreasing from the air side to the separator side. Such a distribution of the solid product means that although the pores toward the separator side remain open, the pores at the air side will be blocked first with an increase in the discharge capacity, terminating the discharge process and resulting in a low discharge capacity. In this work, we design and fabricate a cathode structure with a stepwise gradient pore distribution (pore size reducing from 500 to 300 and 100 nm) by mixing carbon powder and nanotubes. The gradient porous cathode enables the capacity of a non-aqueous Lithium-Air Battery discharging at 0.1 mA/cm 2 to be 19.2% higher than that by a uniform porous cathode (~ 100 nm in pore size) and 82.3% higher than that by a uniform porous cathode (~ 500 nm in pore size). The SEM image analysis suggests that the increased discharge capacity can be mainly attributed to the fact that the gradient cathode can not only increase oxygen transport pathways but also retain a sufficiently large specific surface area.

Wei Shyy - One of the best experts on this subject based on the ideXlab platform.

  • effects of moist air on the cycling performance of non aqueous lithium air batteries
    Applied Energy, 2016
    Co-Authors: Wei Shyy, Tianshou Zhao, Ruihan Zhang
    Abstract:

    Most non-aqueous Lithium-Air batteries reported in the literature are limited to operating with pure oxygen. To practically operate the Battery in ambient air, understanding how the Battery’s performance varies with humidity of moist air is essential. Here we study the effects of moist air on the cycling performance through operating a non-aqueous Lithium-Air Battery with a stable anode and a nano-structured RuO2/NiO cathode at various relative humidities. Results show that in the dry air, the discharge and charge terminal voltages are around 2.51 and 4.12V, respectively, but change to 2.79 and 3.87V when the relative humidity reaches 84%. The energy efficiencies corresponding to the dry air and the relative humidity of 84% are 66.2% and 73.8%, respectively. The improved performance is found to be mainly due to the increased fraction of LiOH among the discharge products at high relative humidities. The discharge voltage for the formation of LiOH is higher than that for the formation of Li2O2, while the charge voltage for the decomposition of LiOH is lower than that for the decomposition of Li2O2. The results suggest that to enable a non-aqueous Lithium-Air Battery to operate in moist air, in addition to protecting the lithium anode from water, designing a cathode with electrocatalytic activities for the decomposition of both Li2O2 and LiOH is required.

  • a nano structured ruo2 nio cathode enables the operation of non aqueous lithium air batteries in ambient air
    Energy and Environmental Science, 2016
    Co-Authors: Wei Shyy, Tianshou Zhao
    Abstract:

    We report a cathode composed of RuO2 nanoparticle-decorated NiO nanosheets for a non-aqueous lithium–air Battery. Unlike most of the previously reported non-aqueous lithium–air batteries that are operated with pure oxygen only, we demonstrate that the present cathode enables the Battery to be truly operated in ambient air at 500 mA h g−1 for 200 cycles (800 h), with stable coulombic efficiency (100%) and high energy efficiency (∼75%). The stellar performance is attributed to the favorable combination of RuO2 nanoparticles and NiO nanosheets, which not only catalyzes the oxygen reduction and evolution reactions, but also promotes the decomposition of the side products, including lithium hydroxide and carbonate formed from water and carbon dioxide in the air during discharge.

  • A nano-structured RuO2/NiO cathode enables the operation of non-aqueous lithium–air batteries in ambient air
    Energy & Environmental Science, 2016
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei, Xingbao Zhu
    Abstract:

    We report a cathode composed of RuO2 nanoparticle-decorated NiO nanosheets for a non-aqueous lithium–air Battery. Unlike most of the previously reported non-aqueous lithium–air batteries that are operated with pure oxygen only, we demonstrate that the present cathode enables the Battery to be truly operated in ambient air at 500 mA h g−1 for 200 cycles (800 h), with stable coulombic efficiency (100%) and high energy efficiency (∼75%). The stellar performance is attributed to the favorable combination of RuO2 nanoparticles and NiO nanosheets, which not only catalyzes the oxygen reduction and evolution reactions, but also promotes the decomposition of the side products, including lithium hydroxide and carbonate formed from water and carbon dioxide in the air during discharge.

  • Discharge product morphology versus operating temperature in non-aqueous Lithium-Air batteries
    Journal of Power Sources, 2015
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei
    Abstract:

    Abstract During the discharge process of non-aqueous Lithium-Air batteries, a solid product, Li 2 O 2 , forms in the pores of the porous cathode, and eventually causes the discharge process to cease. During the charge process, solid Li 2 O 2 needs to be electrochemically oxidized. The morphology of the discharge product is, therefore, critically related to the capacity and reversibility of the Battery. In this work, we experimentally show that for a given design of the cathode, the shape of the discharge product Li 2 O 2 at a given discharge current density remains almost unchanged with a change in the operating temperature, but the size decreases with an increase in the temperature. We also demonstrate that the product shape varies with the discharge current density at a given temperature. The practical implication of these findings is that the capacity, charge voltage, and cyclability of a given non-aqueous Lithium-Air Battery are affected by the operating temperature.

  • A gradient porous cathode for non-aqueous Lithium-Air batteries leading to a high capacity
    Electrochemistry Communications, 2014
    Co-Authors: Peng Tan, Zhaohuan Wei, Wei Shyy, Tianshou Zhao
    Abstract:

    Abstract In conventional porous cathodes of non-aqueous Lithium-Air batteries, the higher discharge reaction rate in the oxygen richer region will result in a gradient distribution of the solid product, Li 2 O 2 , decreasing from the air side to the separator side. Such a distribution of the solid product means that although the pores toward the separator side remain open, the pores at the air side will be blocked first with an increase in the discharge capacity, terminating the discharge process and resulting in a low discharge capacity. In this work, we design and fabricate a cathode structure with a stepwise gradient pore distribution (pore size reducing from 500 to 300 and 100 nm) by mixing carbon powder and nanotubes. The gradient porous cathode enables the capacity of a non-aqueous Lithium-Air Battery discharging at 0.1 mA/cm 2 to be 19.2% higher than that by a uniform porous cathode (~ 100 nm in pore size) and 82.3% higher than that by a uniform porous cathode (~ 500 nm in pore size). The SEM image analysis suggests that the increased discharge capacity can be mainly attributed to the fact that the gradient cathode can not only increase oxygen transport pathways but also retain a sufficiently large specific surface area.

Zhong Kuan Luo - One of the best experts on this subject based on the ideXlab platform.

  • Study on the Mixed Electrolyte of N,N-Dimethylacetamide/Sulfolane and Its Application in Aprotic Lithium-Air Batteries.
    ACS omega, 2017
    Co-Authors: Fang Wang, Houzhen Chen, Riguo Mei, Huang Yang, Zhong Kuan Luo
    Abstract:

    Aprotic lithium–air batteries have recently drawn considerable attention due to their ultrahigh specific energy. However, the chemical and electrochemical instability of the electrolyte is one of the most critical issues that need to be overcome. To increase the stability and maintain a relatively high conductivity of the lithium ion, a mixed electrolyte of sulfolane (TMS) and N,N-dimethylacetamide (DMA) was evaluated and tested in an aprotic lithium–air Battery. The physical and chemical characterizations showed that the mixed electrolyte exhibited a relatively low viscosity, high ionic conductivity and oxygen solubility, and good stability. In addition, it was found that lithium–air batteries with an optimized electrolyte composition (DMA/TMS = 20:80, % v/v) showed a better cycle life and lower charge overpotential as compared to those with electrolytes with a single solvent, either DMA or TMS.

  • Improving the performance of a non-aqueous Lithium-Air Battery by defective titanium dioxides with oxygen vacancies
    Electrochimica Acta, 2016
    Co-Authors: Fang Wang, Yang Hai Xu, Qi Xing Wu, Chunli Yin, Haojun Li, Jie Fang, Yang Huang, Zhong Kuan Luo
    Abstract:

    In this work, we proposed using titanium dioxides (TiO2) with oxygen vacancies (H-TiO2) as cathode catalysts to improve the electrochemical performance of non-aqueous Lithium-Air batteries. Such H-TiO2 catalysts were attained by a facile heat treatment of rutile TiO2 and the existence of vacancies was confirmed by Raman spectra and X-ray photoelectron spectroscopy (XPS). It was demonstrated that due to the presence of defects which can facilitate the adsorption and dissociation of oxygen, the in-house Lithium-Air Battery with H-TiO2 can be discharged at the current densities of 0.3 and 0.5 mA cm-2 while maintaining the specific capacities of 3.2 and 2.8 mAh cm-2, respectively, much higher than those of the batteries without catalysts or with pristine rutile TiO2. In addition, the cycling test showed that the Battery with H-TiO2 can undergo 400 and 372 cycles, respectively, at the current densities of 0.3 and 0.5 mA cm-2 with a fixed specific capacity of 0.1 mAh cm-2 and a cutoff discharge voltage of 2.0 V.

  • A dual pore carbon aerogel based air cathode for a highly rechargeable Lithium-Air Battery
    Journal of Power Sources, 2014
    Co-Authors: Fang Wang, Chun Sheng Liang, Zhong Kuan Luo, Yan Pang, Dong Liu, Jing Chen, Xianghua Zhang
    Abstract:

    Cathode structure plays a vital role in Lithium-Air Battery for that it can provide space for discharged products accommodation and free path for oxygen, e− and Li+ transport. However, pore blockage, cathode passivation and degradation all result in low discharge rates and poor cycling capability. To get rid of these predicaments, a novel highly conductive dual pore carbon aerogel based air cathode is fabricated to construct a Lithium-Air Battery, which exhibits 18 to 525 cycles in the LiTFSI/sulfolane electrolyte at a current density varying from 1.00 mA cm−2 to 0.05 mA cm−2, accompanied by a high energy efficiency of 78.32%. We postulate that the essence lies in that the as-prepared air cathode inventively create a suitable tri-phase boundary reaction zone, facilitating oxygen and Li+ diffusion in two independant pore channels, thus realizing a relative higher discharge rate capability, lower pore blockage and cathode passivation. Further, pore structure, carbon loading, rate capability, discharge depth and the air's effect are exploited and coordinated, targeting for a high power and reversible Lithium-Air Battery. Such nano-porous carbon aerogel air cathode of novel dual pore structure and material design is expected to be an attractive alternative for Lithium-Air batteries and other lithium based batteries.

  • Optimizing Main Materials for a Lithium‐Air Battery of High Cycle Life
    Advanced Functional Materials, 2013
    Co-Authors: Zhong Kuan Luo, Chun Sheng Liang, Hong Yuan Sun, Fang Wang, Chen Jing, Dong Liu, Hui Yang, Xianping Fan
    Abstract:

    By optimizing the main materials in Lithium-Air batteries, namely sulfolane as electrolyte solvent, lithium bis(trifl uoromethanesulfonyl)imide (LiTFSI) as electrolyte salt, carbon paper as current collector, and Li 2 O 2 ‐C hybrids as positive electrode materials, a performance of 800 cycles with a specifi c capacity of 1000 mAh g 1 (based on the total mass of positive electrode materials) and an average energy effi ciency of 74.72% has been achieved in this work and for the fi rst time reported in the fi eld of Lithium-Air Battery. Sulfolane-based electrolyte and carbon paper current collector play the most critical role in building such a Lithium-Air Battery of high cycle life. The fi ndings described here are expected to benefi t the pursuit of green, sustainable, and highperformance Lithium-Air batteries.

  • Research Progress of Lithium-Air Battery: Research Progress of Lithium-Air Battery
    Journal of Inorganic Materials, 2013
    Co-Authors: Fang Wang, Chun Sheng Liang, Hong Yuan Sun, Huiqun Cao, Zhong Kuan Luo
    Abstract:

    With the increasing demand for high-performance Battery by electric vehicle and the energy storage of power grid, the Lithium-Air Battery with ultra-high specific energy has received more and more attention. To develop safe and practical Lithium-Air Battery with good cycle performance, researchers have done plenty of exploratory work on the corresponding cathode materials, electrolyte, catalyst and waterproof oxygen permeation membrane, etc. Among all the work, finding stable electrolyte and minimizing discharge products’ passivation are the most critical issues. In this paper, based on the aprotic electrolyte architecture, the latest researches on the mentioned respects of the Lithium-Air Battery are reviewed. In addition, the general development of other three architectures is introduced. At last, the future challenges in development of Lithium-Air Battery are proposed

Zhaohuan Wei - One of the best experts on this subject based on the ideXlab platform.

  • A nano-structured RuO2/NiO cathode enables the operation of non-aqueous lithium–air batteries in ambient air
    Energy & Environmental Science, 2016
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei, Xingbao Zhu
    Abstract:

    We report a cathode composed of RuO2 nanoparticle-decorated NiO nanosheets for a non-aqueous lithium–air Battery. Unlike most of the previously reported non-aqueous lithium–air batteries that are operated with pure oxygen only, we demonstrate that the present cathode enables the Battery to be truly operated in ambient air at 500 mA h g−1 for 200 cycles (800 h), with stable coulombic efficiency (100%) and high energy efficiency (∼75%). The stellar performance is attributed to the favorable combination of RuO2 nanoparticles and NiO nanosheets, which not only catalyzes the oxygen reduction and evolution reactions, but also promotes the decomposition of the side products, including lithium hydroxide and carbonate formed from water and carbon dioxide in the air during discharge.

  • A high-rate and long cycle life solid-state lithium–air Battery
    Energy & Environmental Science, 2015
    Co-Authors: Xingbao Zhu, Tianshou Zhao, Zhaohuan Wei, Peng Tan
    Abstract:

    Lithium–air batteries are currently limited to being operated under pure oxygen rather than ambient air, primarily due to the discharge product, lithium peroxide, reacting with water and carbon dioxide in ambient air to produce lithium carbonate, which renders the Battery irreversible. A solution to this debilitating problem is to install an oxygen selective membrane that only allows oxygen to enter the Battery. While theoretically sound, this method causes a significant decrease in the oxygen transfer rate due to a limited oxygen permeation area of the planar membrane and an increase in the oxygen transport distance from the membrane to the reaction sites. In this work, we create a novel solid-state lithium–air Battery having a porous LATP cathode, designed using silicone-oil film coated pores that block water vapor and carbon dioxide from reaching reaction sites, but allow a high rate of oxygen transfer owing to an increase in the specific area of the films and a reduced oxygen transfer resistance. This Battery can operate in ambient air at 5000 mA h gcarbon−1 for 50 cycles (125 days). Moreover, the charge/discharge rate reaches as high as 2.0 mA cm−2, a value which is about 40 times higher than that of conventional lithium–air batteries having an oxygen selective membrane external to the cathode.

  • Discharge product morphology versus operating temperature in non-aqueous Lithium-Air batteries
    Journal of Power Sources, 2015
    Co-Authors: Peng Tan, Tianshou Zhao, Wei Shyy, Zhaohuan Wei
    Abstract:

    Abstract During the discharge process of non-aqueous Lithium-Air batteries, a solid product, Li 2 O 2 , forms in the pores of the porous cathode, and eventually causes the discharge process to cease. During the charge process, solid Li 2 O 2 needs to be electrochemically oxidized. The morphology of the discharge product is, therefore, critically related to the capacity and reversibility of the Battery. In this work, we experimentally show that for a given design of the cathode, the shape of the discharge product Li 2 O 2 at a given discharge current density remains almost unchanged with a change in the operating temperature, but the size decreases with an increase in the temperature. We also demonstrate that the product shape varies with the discharge current density at a given temperature. The practical implication of these findings is that the capacity, charge voltage, and cyclability of a given non-aqueous Lithium-Air Battery are affected by the operating temperature.

  • A gradient porous cathode for non-aqueous Lithium-Air batteries leading to a high capacity
    Electrochemistry Communications, 2014
    Co-Authors: Peng Tan, Zhaohuan Wei, Wei Shyy, Tianshou Zhao
    Abstract:

    Abstract In conventional porous cathodes of non-aqueous Lithium-Air batteries, the higher discharge reaction rate in the oxygen richer region will result in a gradient distribution of the solid product, Li 2 O 2 , decreasing from the air side to the separator side. Such a distribution of the solid product means that although the pores toward the separator side remain open, the pores at the air side will be blocked first with an increase in the discharge capacity, terminating the discharge process and resulting in a low discharge capacity. In this work, we design and fabricate a cathode structure with a stepwise gradient pore distribution (pore size reducing from 500 to 300 and 100 nm) by mixing carbon powder and nanotubes. The gradient porous cathode enables the capacity of a non-aqueous Lithium-Air Battery discharging at 0.1 mA/cm 2 to be 19.2% higher than that by a uniform porous cathode (~ 100 nm in pore size) and 82.3% higher than that by a uniform porous cathode (~ 500 nm in pore size). The SEM image analysis suggests that the increased discharge capacity can be mainly attributed to the fact that the gradient cathode can not only increase oxygen transport pathways but also retain a sufficiently large specific surface area.