Technical Field The present disclosure relates to a slurry with improved dispersibility and its use, and more particularly, to a slurry with improved dispersibility of inorganic particles by controlling a particle diameter of an inorganic matter in the slurry including inorganic 5 particles, an organic binder polymer and a solvent as ingredients to adjust a viscosity of the slurry to a predetermined range, and a separator or an electrode compound for an electrochemical device manufactured using the slurry. The present application claims priority to Korean Patent Application No. 10-2012-0138434 filed in the Republic of Korea on November 30, 2012 and Korean Patent 10 Application No. 10-2013-0147428 filed in the Republic of Korea on November 29, 2013, the disclosures of which are incorporated herein by reference. Background Art 15 With the growing demand of batteries as an energy source, the interest in rechargeable electrochemical devices is increasing, and in particular, there is a further increase in the demand for and interest in lithium secondary batteries. A lithium secondary battery includes an electrode assembly composed of a cathode, a separator, and an anode. The separator may be manufactured by coating a porous polymer 20 substrate with a slurry including inorganic particles and an organic binder polymer, followed by drying, and the cathode and the anode are manufactured by applying, to an electrode current collector, a slurry for an electrode compound including inorganic particles serving as an active material and an organic binder polymer. The slurry includes the inorganic particles with the aim to intercalcate/deintercalate a lithium ion or improve ionic conductivity of an 25 electrolyte solution, but the inorganic particles tend to sink over time. Accordingly, when the inorganic particles are not dispersed in the slurry uniformly or sink due to low dispersion stability, condensation or sediment occurs after the slurry is applied to the porous polymer substrate or the electrode current collector (hereinafter, collectively referred to as a 'substrate'). As a result, an adhesive strength between the inorganic particles in the slurry and 30 the substrate reduces, and as charging and discharging of the battery proceeds, separation between the inorganic particles or between the inorganic particles and the substrate occurs, and consequently, the inorganic particles do not fulfill their function. To solve the problem, studies have been conducted to improve dispersibility of 3 inorganic particles, for example, a technology that uses a surfactant as a dispersant when dispersing an active material and carbon black in a solvent. However, because adsorption of a surfactant on the particle surface is low, a large amount of surfactants is required to achieve good dispersion stability. As a result, an amount of inorganic particles that can be included in a slurry relatively reduces, and consequently, inorganic particles do not tend to fulfill their 5 intrinsic function. Also, if adsorption of a surfactant on particles is insufficient, inorganic particles are prone to agglomeration. Also, a general surfactant has a remarkably low dispersion effect in an organic solvent, compared to dispersion in a water-soluble solution. DISCLOSURE 10 Technical Problem The present disclosure is designed to solve the problem that, in a slurry including inorganic particles as an ingredient, the inorganic particles do not fulfill their intrinsic function due to premature sinking by insufficient dispersibility of the inorganic particles. 15 That is, the present disclosure is directed to providing a slurry with improved dispersibility of inorganic particles, and a separator and an electrode compound for an electrochemical device with excellent battery performance, manufactured using the slurry. Technical Solution 20 According to an exemplary embodiment of the present disclosure, provided is a slurry including inorganic particles, an organic binder polymer, and a solvent, wherein the inorganic particles have a diameter in a range of 0.01 μm to 15 μm, and the slurry has a viscosity of which a lower bound is a value obtained from the following Equation based on the diameter of the inorganic particles and an upper bound is 10,000 cP: 25 [Equation 1] η ≥ 40 d 2 where η denotes a viscosity of a slurry, and d denotes an average diameter of inorganic particles. The slurry is characterized by including 10 to 50 parts by weight of the inorganic 30 particles and 1 to 10 parts by weight of the organic binder polymer based on 100 parts by weight of the solvent. The inorganic particles may be selected from the group consisting of an inorganic particle having a dielectric constant greater than or equal to 5, an inorganic particle having a 4 lithium ion delivery capability, and a mixture thereof. The inorganic particle having the dielectric constant greater than or equal to 5 may be any one selected from the group consisting of BaTiO3, Pb(Zrx,Ti1-x)O3 (PZT, 0