Separator having no separator substrate and electrochemical device including the same
Disclosed herein is a separator for electrochemical devices, configured to guarantee electrical insulation between a positive electrode and a negative electrode, wherein the separator includes no polyolefin substrate, and includes inorganic particles, a binder for coupling between the inorganic particles, and a crosslinking agent.
1. A separator for electrochemical devices, configured to provide electrical insulation between a positive electrode and a negative electrode, wherein
the separator comprises no polyolefin substrate, and comprises inorganic particles, a binder for coupling between the inorganic particles, and a crosslinking agent,
wherein the crosslinking agent is a polymer material represented by Formula 1 having a weight average molecular weight of 1,000 to 100,000:
wherein in the Formula 1, x is an integer of 1 to 100, y is an integer of 0 to 30, z is an integer of 1 to 1,000, and p is an integer which varies depending on the weight average molecular weight.
2. The separator according to claim 1 , wherein the inorganic particles are high-dielectric inorganic particles having a dielectric constant of 1 or more, inorganic particles having piezoelectricity, inorganic particles having lithium ion transfer ability, alumina hydrate, or a mixture of two or more thereof.
3. The separator according to claim 1 , wherein the binder is at least one selected from a group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polyvinylidene fluoride-chlorotrifluoroethylene, polymethyl methacrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, ethylene vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, acrylonitrile butadiene styrene copolymer, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluoro rubber, and polyimide.
4. The separator according to claim 1 , wherein a reaction temperature of a crosslinking reaction of the crosslinking agent is 120° C. to 160° C.
5. The separator according to claim 1 , wherein the separator further comprises an initiator for a crosslinking reaction with the crosslinking agent.
6. The separator according to claim 5 , wherein the initiator is an azo-based compound or a peroxide-based compound.
7. The separator according to claim 6 , wherein the azo-based compound is at least one selected from among 2,2′-azobis(2-methylbutyronitrile), 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile).
8. The separator according to claim 7 , wherein the azo-based compound is 2,2′-azobis(isobutyronitrile) or 2,2′-azobis(2,4-dimethylvaleronitrile).
9. The separator according to claim 6 , wherein the peroxide-based compound is at least one selected from among tetramethylbutyl peroxyneodecanoate, bis(4-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, butyl peroxyneodecanoate, dipropyl peroxydicarbonate, diisopropyl peroxydicarbonate, diethoxyethyl peroxydicarbonate, diethoxyhexyl peroxydicarbonate, hexyl peroxydicarbonate, dimethoxybutyl peroxydicarbonate, bis(3-methoxybutyl) peroxydicarbonate, dibutyl peroxydicarbonate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, hexyl peroxypivalate, butyl peroxypivalate, trimethylhexanoyl peroxide, dimethylhydroxybutyl peroxyneodecanoate, amyl peroxyneodecanoate, butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, amyl peroxypivalate, t-butyl peroxypivalate, t-amyl peroxy-2-ethylhexanoate, lauroyl peroxide, dilauroyl peroxide, didecanoyl peroxide, benzoyl peroxide, and dibenzoyl peroxide.
10. The separator according to claim 1 , wherein a content of the crosslinking agent is greater than 0 wt % and equal to or less than 15 wt % of a total weight of a solid body in the separator.
11. An electrochemical device comprising the separator according to claim 1 .
12. The separator according to claim 1 , wherein the inorganic particles comprise alumina hydrate, wherein the alumina hydrate is selected from gibbsite γ-Al(OH) 3 , bayerite Al(OH) 3 , diaspore α-AlOOH, and boehmite γ-AlOOH.