Abstract Electrolytes are essential constituents for safe and reliable battery performance. Curre... more Abstract Electrolytes are essential constituents for safe and reliable battery performance. Current lithium-ion battery (LIB) systems present an inherent safety problem stemming from the use of metal oxide cathodes, which are oxygen sources, and flammable electrolytes based primarily on organic carbonates. Herein we report a novel non-flammable electrolyte formulated by the addition of 30% wt. of methyltributhylphosphonium Bis(trifluoromethanesulfonyl) imide [Bu3MeP][TFSI] ionic liquid (IL) to a standard electrolyte (SE, ethylene carbonate (EC): ethyl methyl carbonate (EMC) 1:1 wt/wt) + 1M LiPF6). The good physicochemical properties of the IL, (i) mitigate the ignition delay and flammability of the proposed electrolyte and (ii) markedly improve the interfacial resistance of the LiMn2O4//Li and LiNi0.8Co0.15Al0.05O2//Li half-cells. The half-cells' performance indicates that the conveyed hybrid electrolyte (HE) retains a higher portion of its energy density (629 vs. 446 Wh.kg−1 for HE and SE in an NCA//Li half-cell, accordingly). At 60°C, [Bu3MeP] [TFSI] considerably improved the cathode performance in terms of capacity (up to 230 mAh.g−1 for NCA) and coulombic efficiency (>99%).
Boron, nitrogen co-doped carbons prepared from original imidazolium tetraphenylborate salts demon... more Boron, nitrogen co-doped carbons prepared from original imidazolium tetraphenylborate salts demonstrated high rate capabilities versus Li+/Li.
Nowadays, our lives have become completely dependent on energy. That is the reason why special at... more Nowadays, our lives have become completely dependent on energy. That is the reason why special attention was focused to the development of clean sustainable energy sources due to the depletion of fossil fuel and its negative impact on the environment. In this regard, many electrochemical storage systems were explored. However, lithium ion batteries are the most effective systems dominating the battery market and used in several applications like cellphones, laptops, digital cameras, etc. The performance of such electrochemical energy storage system strongly depends on the used electrode material. Here we will present our recently obtained results on phosphates as safe and cost-efficient electrode materials for the battery technology.
Abstract Li-rich layered oxides Li1+xMO2 (M: Ni, Co, Mn) being a combination between Li2MnO3 and ... more Abstract Li-rich layered oxides Li1+xMO2 (M: Ni, Co, Mn) being a combination between Li2MnO3 and LiMO2, are considered as attractive high-capacity electrode materials for Lithium ion batteries. Here, we present the composition Li1.17Ni0.21Mn0.54Co0.08O2 with low cobalt content. The synthesis process was optimized by varying the pH of the co-precipitation step and pure phase was obtained only for pH = 11.3. The morphology of the material consists on the agglomeration of quasi-spherical particles an average particle size of 157 nm. The electrochemical properties of this electrode material were investigated, and a specific capacity of 250 mAh/g was recorded in the voltage range of 2–4.8 V. While the first charge process evidenced a potential plateau at 4.5 V corresponding to the oxygen redox activity, the subsequent electrochemical behavior is governed by Ni2+/Ni4+ and Co3+/Co4+ redox couples. When cycled for 40 charge/discharge cycles at 0.1C rate, the capacity retention is still good and remains around 85% with a coulombic efficiency of around 98%. The comparison of the obtained performances with those of existing Li-rich electrode materials show the excellent features of the studied Li-rich material for the next generation Lithium-ion batteries.
Continuing the exploration of safe phosphonium-based electrolytes for lithium-ion battery (LIB) a... more Continuing the exploration of safe phosphonium-based electrolytes for lithium-ion battery (LIB) applications, we present herein the results of a nonflammable electrolyte containing methyl tributylphosphosphonium Bis(trifluoromethanesulfonyl) imide (Bu3MeP-TFSI) ionic liquid (IL) EC/EMC (1:1, wt) with 1 M LiPF6 on lithium manganese oxide (LMO), lithium nickel manganese oxide (LMNO), graphite, and lithium metal. A high wt% (10–30%) of IL propagates dead Li formation as opposed to 5% wt IL where superior performance to a standard commercial electrode was observed for 150 h of continuous cycling at 0.5 mAh cm−2. For the LMO//Li half-cell, the presence of the IL allowed cathode operation at high potentials (> 4.3 V vs. Li/Li+) with moderate capacity retention (90%). Despite the poor interface that arises from the viscosity of the phosphonium IL, at 5% wt, the LMNO//Li half-cell performance was reversible (DLi+ = 4.83 × 10–13 cm2 s−1) with a capacity retention of 86%, coulombic effici...
Abstract Electrolytes are essential constituents for safe and reliable battery performance. Curre... more Abstract Electrolytes are essential constituents for safe and reliable battery performance. Current lithium-ion battery (LIB) systems present an inherent safety problem stemming from the use of metal oxide cathodes, which are oxygen sources, and flammable electrolytes based primarily on organic carbonates. Herein we report a novel non-flammable electrolyte formulated by the addition of 30% wt. of methyltributhylphosphonium Bis(trifluoromethanesulfonyl) imide [Bu3MeP][TFSI] ionic liquid (IL) to a standard electrolyte (SE, ethylene carbonate (EC): ethyl methyl carbonate (EMC) 1:1 wt/wt) + 1M LiPF6). The good physicochemical properties of the IL, (i) mitigate the ignition delay and flammability of the proposed electrolyte and (ii) markedly improve the interfacial resistance of the LiMn2O4//Li and LiNi0.8Co0.15Al0.05O2//Li half-cells. The half-cells' performance indicates that the conveyed hybrid electrolyte (HE) retains a higher portion of its energy density (629 vs. 446 Wh.kg−1 for HE and SE in an NCA//Li half-cell, accordingly). At 60°C, [Bu3MeP] [TFSI] considerably improved the cathode performance in terms of capacity (up to 230 mAh.g−1 for NCA) and coulombic efficiency (>99%).
Boron, nitrogen co-doped carbons prepared from original imidazolium tetraphenylborate salts demon... more Boron, nitrogen co-doped carbons prepared from original imidazolium tetraphenylborate salts demonstrated high rate capabilities versus Li+/Li.
Nowadays, our lives have become completely dependent on energy. That is the reason why special at... more Nowadays, our lives have become completely dependent on energy. That is the reason why special attention was focused to the development of clean sustainable energy sources due to the depletion of fossil fuel and its negative impact on the environment. In this regard, many electrochemical storage systems were explored. However, lithium ion batteries are the most effective systems dominating the battery market and used in several applications like cellphones, laptops, digital cameras, etc. The performance of such electrochemical energy storage system strongly depends on the used electrode material. Here we will present our recently obtained results on phosphates as safe and cost-efficient electrode materials for the battery technology.
Abstract Li-rich layered oxides Li1+xMO2 (M: Ni, Co, Mn) being a combination between Li2MnO3 and ... more Abstract Li-rich layered oxides Li1+xMO2 (M: Ni, Co, Mn) being a combination between Li2MnO3 and LiMO2, are considered as attractive high-capacity electrode materials for Lithium ion batteries. Here, we present the composition Li1.17Ni0.21Mn0.54Co0.08O2 with low cobalt content. The synthesis process was optimized by varying the pH of the co-precipitation step and pure phase was obtained only for pH = 11.3. The morphology of the material consists on the agglomeration of quasi-spherical particles an average particle size of 157 nm. The electrochemical properties of this electrode material were investigated, and a specific capacity of 250 mAh/g was recorded in the voltage range of 2–4.8 V. While the first charge process evidenced a potential plateau at 4.5 V corresponding to the oxygen redox activity, the subsequent electrochemical behavior is governed by Ni2+/Ni4+ and Co3+/Co4+ redox couples. When cycled for 40 charge/discharge cycles at 0.1C rate, the capacity retention is still good and remains around 85% with a coulombic efficiency of around 98%. The comparison of the obtained performances with those of existing Li-rich electrode materials show the excellent features of the studied Li-rich material for the next generation Lithium-ion batteries.
Continuing the exploration of safe phosphonium-based electrolytes for lithium-ion battery (LIB) a... more Continuing the exploration of safe phosphonium-based electrolytes for lithium-ion battery (LIB) applications, we present herein the results of a nonflammable electrolyte containing methyl tributylphosphosphonium Bis(trifluoromethanesulfonyl) imide (Bu3MeP-TFSI) ionic liquid (IL) EC/EMC (1:1, wt) with 1 M LiPF6 on lithium manganese oxide (LMO), lithium nickel manganese oxide (LMNO), graphite, and lithium metal. A high wt% (10–30%) of IL propagates dead Li formation as opposed to 5% wt IL where superior performance to a standard commercial electrode was observed for 150 h of continuous cycling at 0.5 mAh cm−2. For the LMO//Li half-cell, the presence of the IL allowed cathode operation at high potentials (> 4.3 V vs. Li/Li+) with moderate capacity retention (90%). Despite the poor interface that arises from the viscosity of the phosphonium IL, at 5% wt, the LMNO//Li half-cell performance was reversible (DLi+ = 4.83 × 10–13 cm2 s−1) with a capacity retention of 86%, coulombic effici...
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