Rechargeable batteries are essential energy storage devices that power portable devices and electrical vehicles throughout the wo rld.In general,it is thought that the electrochemical performance of recha rgeable batt...Rechargeable batteries are essential energy storage devices that power portable devices and electrical vehicles throughout the wo rld.In general,it is thought that the electrochemical performance of recha rgeable batteries is mostly determined by the electrodes within them and that the electrolyte plays a relatively passive role.However,ion transport and storage can be greatly influenced by the electrolyte solution structure,specifically,ion solvation within the bulk and ion desolvation across the electrode/electrolyte interfaces.Herein,we studied the role of the electrolyte as an active component of electrochemical energy storage devices.We found that with an appropriate electrolyte formulation,ion storage in disordered carbonaceous anode materials can occur spontaneously without externally supplied electrical energy.Reduced graphene oxide(RGO)in an ether-based electrolyte demonstrates'spontaneous'ion storage behaviors of adsorbing and inserting the solvated ions utilizing facilitated permeability and wettability of RGO,which results in Coulombic efficiency of~145%due to additional charging capacity of~180 mAh g^(-1)during electrochemical processes.The unexpected spontaneous ion storage behavior was extensively investigated using a combination of electrochemical analyses and diagnostics,advanced characterizations,and computational simulation.We believe the spontaneous ion storage behavior offers a new way to further improve the energy efficiency of practical rechargeable batteries.展开更多
Cobalt phosphide （COP） nanoparticles which were uniformly embedded in N-doped C nanosheets （CNSs） were fabricated via the simple one-step calcination of a Co-based metal-organic framework （MOF） and red P and exh...Cobalt phosphide （COP） nanoparticles which were uniformly embedded in N-doped C nanosheets （CNSs） were fabricated via the simple one-step calcination of a Co-based metal-organic framework （MOF） and red P and exhibited a high capacity, fast kinetics, and a long cycle life. This CoP/CNS composite contained small CoP particles （approximately 11.3 nm） and P-C bonds. When its electrochemical properties were evaluated by testing CoP/Na coin cells, the composite delivered a Na-storage capacity of 598 mAh·g-1 at 0.1 A·g-1 according to the total mass of the composite, which means that the capacity of pure CoP reached 831 mAh·g-1 The composite also exhibited a high rate capability and long-term cyclability （174 mAh·g-1 at 20 A·g-1 and 98.5% capacity retention after 900 cycles at 1 A·g-1）, which are commonly attributed to robust P-C bonding and highly conductive CNSs. When the reaction mechanism of the CoP/CNS composite was investigated, a conversion reaction expressed as CoP ＋ 3Na＋ ＋ 3e＋＋ Co ＋ Na3P was observed. The outstanding Na-storage properties of the CoP/CNS composite may suggest a new strategy for developing high-performance anode materials for Na-ion batteries.展开更多
基金supported by the faculty research fund of Sejong Universityfunding from the National Research Foundation of Korea(NRF)under grant number NRF-2022R1F1A1071444+2 种基金funding from NRF under grant numbers NRF-2022R1A2B5B03001781Funding provided by the Department of Energy Office of Energy EfficiencyRenewable Energy Vehicles Technology Office。
文摘Rechargeable batteries are essential energy storage devices that power portable devices and electrical vehicles throughout the wo rld.In general,it is thought that the electrochemical performance of recha rgeable batteries is mostly determined by the electrodes within them and that the electrolyte plays a relatively passive role.However,ion transport and storage can be greatly influenced by the electrolyte solution structure,specifically,ion solvation within the bulk and ion desolvation across the electrode/electrolyte interfaces.Herein,we studied the role of the electrolyte as an active component of electrochemical energy storage devices.We found that with an appropriate electrolyte formulation,ion storage in disordered carbonaceous anode materials can occur spontaneously without externally supplied electrical energy.Reduced graphene oxide(RGO)in an ether-based electrolyte demonstrates'spontaneous'ion storage behaviors of adsorbing and inserting the solvated ions utilizing facilitated permeability and wettability of RGO,which results in Coulombic efficiency of~145%due to additional charging capacity of~180 mAh g^(-1)during electrochemical processes.The unexpected spontaneous ion storage behavior was extensively investigated using a combination of electrochemical analyses and diagnostics,advanced characterizations,and computational simulation.We believe the spontaneous ion storage behavior offers a new way to further improve the energy efficiency of practical rechargeable batteries.
文摘Cobalt phosphide （COP） nanoparticles which were uniformly embedded in N-doped C nanosheets （CNSs） were fabricated via the simple one-step calcination of a Co-based metal-organic framework （MOF） and red P and exhibited a high capacity, fast kinetics, and a long cycle life. This CoP/CNS composite contained small CoP particles （approximately 11.3 nm） and P-C bonds. When its electrochemical properties were evaluated by testing CoP/Na coin cells, the composite delivered a Na-storage capacity of 598 mAh·g-1 at 0.1 A·g-1 according to the total mass of the composite, which means that the capacity of pure CoP reached 831 mAh·g-1 The composite also exhibited a high rate capability and long-term cyclability （174 mAh·g-1 at 20 A·g-1 and 98.5% capacity retention after 900 cycles at 1 A·g-1）, which are commonly attributed to robust P-C bonding and highly conductive CNSs. When the reaction mechanism of the CoP/CNS composite was investigated, a conversion reaction expressed as CoP ＋ 3Na＋ ＋ 3e＋＋ Co ＋ Na3P was observed. The outstanding Na-storage properties of the CoP/CNS composite may suggest a new strategy for developing high-performance anode materials for Na-ion batteries.
