LITHIUM ION BATTERY ELECTRODE AND LITHIUM ION BATTERY

An electrode for a lithium-ion battery (100) of the present invention is a high-density electrode for a lithium-ion battery (100) including a collector layer (101), and a negative electrode active material layer (103) which is provided on at least one surface of the collector layer (101) and includes a negative electrode active material, a water-based binder resin, a thickener, and a conductive auxiliary agent, in which a density of the negative electrode active material layer (103) is equal to or more than 1.55 g/cm 3 , and an electrolytic solution soaking time into an electrode, which is measured using the following method 1, is equal to or longer than 10 seconds and equal to or shorter than 55 seconds. (Method 1: In a temperature environment of 25°C, 5 µL of an electrolytic solution obtained by dissolving LiPF 6 as an electrolyte in a solvent mixture of ethylene carbonate and diethyl carbonate (a volume ratio between ethylene carbonate and diethyl carbonate is 3:7) so as to obtain a concentration of 1.0 mol/L is added dropwise to a surface opposite to a collector layer (101) side of the negative electrode active material layer (103) of the electrode for a lithium-ion battery (100) from a location 0.5 cm away from the surface of the negative electrode active material layer (103) in a vertical direction. Next, a time taken for a liquid droplet of the electrolytic solution to become unobservable from the surface of the negative electrode active material layer (103) from the dropwise addition of the electrolytic solution is measured, and the time is considered as the electrolytic solution soaking time into the electrode.)