Abstract: A lithium-ion secondary battery having high capacity and excellent charge and discharge cycle performance is provided. A secondary battery having high capacity is provided. A secondary battery with excellent charge and discharge characteristics is provided. A secondary battery in which a reduction in capacity is suppressed even when a state being charged with a high voltage is held for a long time is provided. In the secondary battery, after constant current charging is performed in an environment at 60° C. with a current value of 0.5 C until a voltage reaches 4.5 V, a charging process of performing constant voltage charging until a current value reaches 0.2 C and a discharging process of performing constant current discharging with a current value of 0.

Abstract: An electrode with little deterioration or a secondary battery with little deterioration is provided. An electrode includes a first region and a second region. The first region includes a particle containing silicon. The second region includes a particle containing silicon and a graphene compound. The second region is in contact with the first region to cover at least part thereof. Alternatively, an electrode includes a plurality of particles containing silicon and a graphene compound. Each of the plurality of particles containing silicon includes a functional group containing oxygen and carbon, a functional group containing oxygen, or a fluorine atom in at least part of the surface. The graphene compound includes at least one of carbon terminated with hydrogen and carbon terminated with fluorine in a plane of the graphene compound. The graphene compound is in contact with the plurality of particles containing silicon to closely cling thereto.

Abstract: A negative electrode with little deterioration is provided. A novel negative electrode is provided. A power storage device with little deterioration is provided. A novel power storage device is provided. The electrode contains silicon, graphite, and a graphene compound. A silicon particle with a particle diameter of less than or equal to 1 µm is attached to a graphite particle with a particle diameter 10 times or more that of the silicon particle. The graphene compound is in contact with the graphite particle so as to cover the silicon particle.

Abstract: A negative electrode active material particle with little deterioration is provided. Alternatively, a novel negative electrode active material particle is provided. Alternatively, a power storage device with little deterioration is provided. Alternatively, a highly safe power storage device is provided. Alternatively, a novel power storage device is provided. The electrode includes an active material and a conductive additive; the active material contains a metal or a compound including one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium; the conductive additive contains a graphene compound; and the graphene compound contains fluorine.

Abstract: A positive electrode active material having a crystal structure that is unlikely to be broken by repeated charging and discharging is provided. A positive electrode active material with high charge and discharge capacity is provided. A positive electrode active material including lithium, cobalt, nickel, magnesium, and oxygen, in which the a-axis lattice constant of an outermost surface layer of the positive electrode active material is larger than the a-axis lattice constant of an inner portion and in which the c-axis lattice constant of the outermost surface layer is larger than the c-axis lattice constant of the inner portion. A rate of change between the a-axis lattice constant of the outermost surface layer and the a-axis lattice constant of the inner portion is preferably larger than 0 and less than or equal to 0.

Abstract: A vehicle component includes a body, a first beam, and a second beam. The body has a first fixture region and a second fixture region. The first beam is formed of a first composite material and has a first beam shape. The first beam is attached to the body and extends between the first fixture region and the second fixture region of the body. The second beam is formed of a second composite material and has a second beam shape that is simple compared to the first beam shape. The second beam is attached to the body and extends between the first fixture region and the second fixture region of the body.

Abstract: A method for drawing and heat-treating an undrawn polyester yarn by drawing the polyester yarn between a heated feed roller and at least one heated draw roller, wherein the surface temperature of the last draw roller is progressively raised from its yarn in-coming side to its yarn out-going side, the yarn is shrunken both on the last draw roller and between the last draw roller and the take-up roller, and the yarn is cooled on the take-up roller. Further, after the method has resumed after being stopped, the running speed of the yarn on the take-up roller is maintained at not more than (100-5.7.times.S)m/min., wherein S is the total shrinkage of the yarn until the yarn heated during the stoppage has been allowed to shrink in the subsequent step. The yarn is then passed over the take-up roller at a running speed of 200 to 1200 m/min.