Composite electrolyte, protective film including composite electrolyte, protected negative electrode including the protective film, and lithium metal battery including the protected

A composite electrolyte, comprising:

• a particle, wherein the particle is positively charged;
• and
• a lithium salt,
• wherein the particle comprises:
• a core;
• and
• a functional group bound to the core via a covalent bond,
• wherein the functional group comprises a positively charged functional group,
• wherein the particle comprises an organic particle,
• wherein a size of the organic particle is in a range of about 10 nanometers to about 100 micrometers,
• wherein the positively charged functional group is represented by Formulae 3 to 10, or a combination thereof:
• and
• wherein a lithium ion mobility of the composite electrolyte is greater than a lithium ion mobility of a comparable composite electrolyte comprising the lithium salt and not comprising the particle.