Electrolytes, anode material particles and methods are provided for improving performance and enhancing the safety of lithium ion batteries. Electrolytes may comprise ionic liquid(s) as additives which protect the anode material particles and possibly bind thereto; and/or may comprise a large portion of fluoroethylene carbonate (FEC) and/or vinylene carbonate (VC) as the cyclic carbonate component, and possibly ethyl acetate (EA) and/or ethyl methyl carbonate (EMC) as the linear component; and/or may comprise composite electrolytes having solid electrolyte particles coated by flexible ionic conductive material. Ionic liquid may be used to pre-lithiate in situ the anode material particles. Disclosed electrolytes improve lithium ion conductivity, prevent electrolyte decomposition and/or prevents lithium metallization on the surface of the anode.