A lithium metal battery, comprising a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode comprises a lithium metal and a protective layer located on at least a part of a surface of the lithium metal, the protective layer comprises a polymer X and a polymer Y, the polymer X comprises a polymer Z and a polymer W, the polymer Z is selected from one or more of polytetrafluoroethylene and a compound represented Formula I, the polymer W is selected from one or more of compounds represented by Formula II and Formula III, and the polymer Y is selected from one or more of polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene: wherein, 0 < m ≤ 2500, 0 < n ≤ 5000, 0 < n' ≤ 5000, 1:25 ≤ 2m:n & 25:1, 1:25 & 2m:n' & 25:1; R 1 is selected from H; branched or unbranched, saturated or unsaturated, substituted or unsubstituted C1-C20 aliphatic groups; saturated or unsaturated, substituted or unsubstituted C3-C9 cycloalkyls; (C=O)OR 4; -SO 3 R 4; and -PO 3 R 4; the cycloalkyls optionally comprise at least one heteroatom selected from S, N, P, and O as a ring member; R 4 is selected from H; branched or unbranched, saturated or unsaturated, substituted or unsubstituted C1-C20 aliphatic groups; and saturated or unsaturated, substituted or unsubstituted C3-C9 cycloalkyls; the cycloalkyls optionally comprise at least one heteroatom selected from S, N, P, and O as a ring member; in R 1 and R 4, substituents of the aliphatic groups and the cycloalkyls each are independently selected from C1-C6 alkyls; linear or branched C1-C6 alkoxies; F; Cl; I; Br; CF 3; CH 2 F; CHF 2; CN; OH; SH; NH 2; oxo; (C=O)R'; SR'; SOR'; SO 2 R'; NHR'; NR'R"; SiRR'R"; SiOR'R"; (R'O) 2 (P=O); (R'O) 2 (P=S); (R'S) 2 ( P=O)'; and BR'R", wherein R, R', and R" of the substituents each are independently selected from linear or branched C 1-6 alkyls; R 2 is selected from H and a methyl; and R 3 is selected from H; branched or unbranched, saturated or unsaturated, substituted or unsubstituted C1-C20 aliphatic groups; and saturated or unsaturated, substituted or unsubstituted C3-C9 cycloalkyls; the cycloalkyls optionally comprise at least one heteroatom selected from S, N, P, and O as a ring member; in R 3, substituents of the aliphatic groups and the cycloalkyls each are independently selected from an aryl; C1-C6 alkyls; linear or branched C1-C6 alkoxies; F; Cl; I; Br; CF 3; CH 2 F; CHF 2; CN; OH; SH; NH 2; oxo; (C=O)R'; SR'; SOR'; SO 2 R'; NHR'; NR'R"; SiRR'R"; SiOR'R"; (R'O) 2 (P=O); (R'O) 2 (P=S); (R'S) 2 ( P=O)'; and BR'R", wherein R, R', and R" of the substituents each are independently selected from linear or branched C 1-6 alkyls. wherein, 0 < m ≤ 2500, 0 < n ≤ 5000, 0 < n' ≤ 5000, 1:25 ≤ 2m:n & 25:1, 1:25 & 2m:n' & 25:1; R 1 is selected from H; branched or unbranched, saturated or unsaturated, substituted or unsubstituted C1-C20 aliphatic groups; saturated or unsaturated, substituted or unsubstituted C3-C9 cycloalkyls; (C=O)OR 4; -SO 3 R 4; and -PO 3 R 4; the cycloalkyls optionally comprise at least one heteroatom selected from S, N, P, and O as a ring member; R 4 is selected from H; branched or unbranched, saturated or unsaturated, substituted or unsubstituted C1-C20 aliphatic groups; and saturated or unsaturated, substituted or unsubstituted C3-C9 cycloalkyls; the cycloalkyls optionally comprise at least one heteroatom selected from S, N, P, and O as a ring member; in R 1 and R 4, substituents of the aliphatic groups and the cycloalkyls each are independently selected from C1-C6 alkyls; linear or branched C1-C6 alkoxies; F; Cl; I; Br; CF 3; CH 2 F; CHF 2; CN; OH; SH; NH 2; oxo; (C=O)R'; SR'; SOR'; SO 2 R'; NHR'; NR'R"; SiRR'R"; SiOR'R"; (R'O) 2 (P=O); (R'O) 2 (P=S); (R'S) 2 ( P=O)'; and BR'R", wherein R, R', and R" of the substituents each are independently selected from linear or branched C 1-6 alkyls; R 2 is selected from H and a methyl; and R 3 is selected from H; branched or unbranched, saturated or unsaturated, substituted or unsubstituted C1-C20 aliphatic groups; and saturated or unsaturated, substituted or unsubstituted C3-C9 cycloalkyls; the cycloalkyls optionally comprise at least one heteroatom selected from S, N, P, and O as a ring member; in R 3, substituents of the aliphatic groups and the cycloalkyls each are independently selected from an aryl; C1-C6 alkyls; linear or branched C1-C6 alkoxies; F; Cl; I; Br; CF 3; CH 2 F; CHF 2; CN; OH; SH; NH 2; oxo; (C=O)R'; SR'; SOR'; SO 2 R'; NHR'; NR'R"; SiRR'R"; SiOR'R"; (R'O) 2 (P=O); (R'O) 2 (P=S); (R'S) 2 ( P=O)'; and BR'R", wherein R, R', and R" of the substituents each are independently selected from linear or branched C 1-6 alkyls.