▎ 摘　　要

NOVELTY - An electrochemical cell comprises an anode, an electrolyte (E1), a polymer membrane separator comprising a microporous polymer, an electrolyte (E2), and a cathode. The polymer membrane separator is positioned between the anode and cathode. Electrolyte (E1) is in contact with the anode and a face (F1) of the polymer membrane separator. Electrolyte (E2) is in contact with the cathode and a face (F2) of the polymer membrane separator. At least one electrolyte comprises a locally-concentrated electrolyte comprising one or more alkali metal salts, a solvent, and a diluent. USE - Electrochemical cell is used as rechargeable lithium metal battery. Uses include but are not limited to electric aircraft, electric vehicle, seacraft, and drones. ADVANTAGE - The electrochemical cell has high power density. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: a bis(benzene-1,2-diol) compound, which is chosen from compounds of formulae (I)-(VIII); the dioxybenzene-containing microporous polymer of formula: -A-AB'-B'n- (IX); and the membrane, which comprises one or more microporous polymers and has a thickness of 0.1-1000 μ m. R =group chosen from groups of formulae (a1)-(a6); X -X =chalcogenide, oxidized chalcogenide, pnictide bonded to 1-20C alkyl or 6-10C aryl, or oxidized pnictide bonded to 1-20C alkyl or 6-10C aryl; R =1-20C alkyl, 2-20C alkenyl, 2-20C alkynyl, 6-10C aryl, 3-8C cycloalkyl, 6-10C aryl-1-20C alkyl, 3-8C cycloalkyl-1-20C alkyl, hetero-1-20C alkyl, 3-8-membered heterocyclyl, 3-8-membered heterocyclyl-1-20C alkyl, 5-8-membered heteroaryl, or 5-8-membered heteroaryl-1-20C alkyl; R ,R =1-20C alkyl, 2-20C alkenyl, 2-20C alkynyl, 6-10C aryl, 3-8C cycloalkyl, 6-10C aryl-1-20C alkyl, 3-8C cycloalkyl-1-20C alkyl, hetero-1-20C alkyl, 3-8-membered heterocyclyl, 3-8-membered heterocyclyl-1-20C alkyl, 5-8-membered heteroaryl, or 5-8-membered heteroaryl-1-20C alkyl; or R +R =4-8C cycloalkyl, 6-10C aryl, 4-8-membered heterocyclyl, or 5-8-membered heteroaryl; n=10-10000; A-A=monomer segment chosen from monomer segments of formulae (a7)-(a16), where at least one is monomer segment chosen from monomer segments (a7)-(a14);and B'-B'=monomer segment chosen from monomer segments of formulae (a17)-(a19).