The cell of the present invention includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The positive electrode includes a porous carbon sheet and a positive electrode active material layer containing a positive electrode active material that is held in pores of the porous carbon sheet. It is preferable that the positive electrode active material layer covers the surface of the porous carbon sheet facing the separator, that a part of the positive electrode active material layer is held in the pores of the porous carbon sheet, and that the surface of the positive electrode active material layer facing the separator has an arithmetic average roughness (Ra) of 10 μm or less or a maximum height roughness (Rz) of 50 μm or less.

A decrease in the capacity of a power storage device is inhibited by adjusting or reducing imbalance in the amount of inserted and extracted carrier ions between positive and negative electrodes, which is caused by decomposition of an electrolyte solution of the negative electrode. Further, the capacity of the power storage device can be restored. Furthermore, impurities in the electrolyte solution can be decomposed with the use of the third electrode. A power storage device including positive and negative electrodes, an electrolyte, and a third electrode is provided. The third electrode has an adequate electrostatic capacitance. The third electrode can include a material with a large surface area. In addition, a method for charging the power storage device including the steps of performing charging by applying a current between the positive and negative electrodes, and performing additional applying a current between the third electrode and the negative electrode is provided.

An electrolyte precursor solution includes a metallic compound containing elements constituting an electrolyte, a solvent capable of dissolving the metallic compound, and an anionic surfactant having a sulfate group (SO.sub.4.sup.2−) bonded to a hydrophobic group R. By reacting such an electrolyte precursor solution with active material particles containing lithium, lithium sulfate derived from the anionic surfactant is interposed at the interface between the surface of the active material particle and the electrolyte so as to enhance the dissociation of lithium ions at the interface, and thus, an excellent ion conductivity can be realized.

An electrolyte precursor solution includes a metallic compound containing elements constituting an electrolyte, a solvent capable of dissolving the metallic compound, and an anionic surfactant having a sulfate group (SO.sub.4.sup.2−) bonded to a hydrophobic group R. By reacting such an electrolyte precursor solution with active material particles containing lithium, lithium sulfate derived from the anionic surfactant is interposed at the interface between the surface of the active material particle and the electrolyte so as to enhance the dissociation of lithium ions at the interface, and thus, an excellent ion conductivity can be realized.

The present invention relates to an electrolytic copper foil for a secondary battery, and a method of producing the same. The electrolytic copper foil for a secondary battery exhibits a little change in a physical property caused by a difference in a crosshead speed when tensile strength and an elongation percentage of the electrolytic copper foil are measured, thereby achieving excellent charging and discharging characteristics of a battery and preventing exfoliation of an active material. The electrolytic copper foil for a secondary battery is produced from a plating solution containing Total Organic Carbon (TOC), cobalt, and iron by using a drum, in which a ratio of the TOC to the cobalt and the iron contained in the electrolytic copper foil follows Formula 1 below.
TOC/(cobalt+iron)=1.3 to 1.5  [Formula 1]

The present invention relates to an electrolytic copper foil for a secondary battery, and a method of producing the same. The electrolytic copper foil for a secondary battery exhibits a little change in a physical property caused by a difference in a crosshead speed when tensile strength and an elongation percentage of the electrolytic copper foil are measured, thereby achieving excellent charging and discharging characteristics of a battery and preventing exfoliation of an active material. The electrolytic copper foil for a secondary battery is produced from a plating solution containing Total Organic Carbon (TOC), cobalt, and iron by using a drum, in which a ratio of the TOC to the cobalt and the iron contained in the electrolytic copper foil follows Formula 1 below.
TOC/(cobalt+iron)=1.3 to 1.5  [Formula 1]

Prelithiation methods and fast charging lithium ion cell are provided, which combine high energy density and high power density. Several structural and chemical modifications are disclosed to enable combination of features that achieve both goals simultaneously in fast charging cells having long cycling lifetime. The cells have anodes with high content of Si, Ge and/or Sn as principal anode material, and cathodes providing a relatively low C/A ratio, with the anodes being prelithiated to have a high lithium content, provided by a prelithiation algorithm. Disclosed algorithms determine lithium content achieved through prelithiation by optimizing the electrolyte to increase cycling lifetime, adjusting energy density with respect to other cell parameters, and possibly reducing the C/A ratio to maintain the required cycling lifetime.

Prelithiation methods and fast charging lithium ion cell are provided, which combine high energy density and high power density. Several structural and chemical modifications are disclosed to enable combination of features that achieve both goals simultaneously in fast charging cells having long cycling lifetime. The cells have anodes with high content of Si, Ge and/or Sn as principal anode material, and cathodes providing a relatively low C/A ratio, with the anodes being prelithiated to have a high lithium content, provided by a prelithiation algorithm. Disclosed algorithms determine lithium content achieved through prelithiation by optimizing the electrolyte to increase cycling lifetime, adjusting energy density with respect to other cell parameters, and possibly reducing the C/A ratio to maintain the required cycling lifetime.

Provided is an electricity-storage module including: a stacked body that includes electrodes which are stacked along a first direction; a sealing body that is provided to the stacked body so as to surround a peripheral edge portion of the electrodes, forms an inner space that stores an electrolytic solution between the electrodes adjacent to each other along the first direction, and seals the inner space; and a reinforcing body that is provided in the electrodes so as to suppress deformation of the electrodes. The electrodes include bipolar electrodes and a negative terminal electrode, the negative terminal electrode includes the electrode plate and a negative electrode provided on the second surface, and is disposed at one end of the stacked body in the first direction such that the second surface faces an inner side of the stacked body in the first direction.

Provided is an electricity-storage module including: a stacked body that includes electrodes which are stacked along a first direction; a sealing body that is provided to the stacked body so as to surround a peripheral edge portion of the electrodes, forms an inner space that stores an electrolytic solution between the electrodes adjacent to each other along the first direction, and seals the inner space; and a reinforcing body that is provided in the electrodes so as to suppress deformation of the electrodes. The electrodes include bipolar electrodes and a negative terminal electrode, the negative terminal electrode includes the electrode plate and a negative electrode provided on the second surface, and is disposed at one end of the stacked body in the first direction such that the second surface faces an inner side of the stacked body in the first direction.