This invention is related to novel electrolytes that are stable with alkali metal anode, graphite anode, silicon anode and various cathode materials in an electrochemical cell. Fluorinated orthoformate electrolytes are electrolyte containing fluorinated orthoformate compounds. In an electrolyte, fluorinated orthoformates has no or very poor solubility with lithium salts, but it can works as diluent with the most known electrolyte solvents (such as carbonates, ethers, phosphates or solvent mixtures, which has a high solvability for lithium salts) to form a localized high concentration electrolyte (LHCE) (which is also called localized superconcentrated electrolyte (LSE)) for lithium metal or lithium ion batteries. These fluorinated orthoformate containing electrolytes are stable with anode (such as lithium, sodium, other alkali metal, graphite, silicon and silicon/graphite anodes), cathode (including both ion intercalation and conversion compounds) and current collectors (such as Cu and Al). They are not only stable with anode by forming a high quality solid electrolyte interphase (SEI) layers, but also stable with high voltage cathodes, thereby improving long-term cycling stability of electrochemical cells. Furthermore, addition of fluorinated orthoformate solvent effectively decreases the electrolyte viscosity and improves the ionic conductivity and wetting ability of the electrolyte. This invention could be widely applied to a variety of electrochemical systems, including lithium (Li) metal batteries, Li ion batteries, Li-S batteries, Li-O2 batteries, sodium metal and sodium ion batteries, magnesium ion batteries, super capacitors, and sensors.