For　realizing　the　commercialization　of　Li-metal　batteries　(LMBs),　the　discharge-blocking　obstacles　under　ultra-low　temperatures　must　be　conquered　besides　the　long-term　reversibility.　Nevertheless,　commercial　carbonate-based　electrolytes　are　not　only　incompatible　with　the　aggressive　Li　anode,　but　also　have　poor　fluidity　at　low　temperatures.　The　prevailing　chain-ether-based　electrolyte　designing　tactics,　such　as　the　common-used　DME,　improve　the　affinity　with　Li　metal　to　some　extent,　but　the　multiple　Lewis-acid　binding　sites　of　chain　ethers　are　not　conducive　to　the　de-solvation　of　Li+.　Herein,　for　the　first　time,　the　cheap　cyclic-type　tetrahydrofuran　(THF)　with　ultra-low　melting　point　and　weak　solvating　power　is　adopted　for　designing　an　original　THF-based　localized　saturated　electrolyte　(Tb-LSCE),　demonstrating　excellent　adaptability　for　low-temperature　LMBs.　Computational　and　experimental　evidence　verify　the　original　solvated　structure　is　modified　via　the　addition　of　fluorinated　antisolvent,　further　contributing　to　the　Li+-THF　de-solvation.　Therefore,　equipped　with　Tb-LSCE,　the　assembled　Li-NCM523　cells　achieve　powerful　anti-polarization　capability　at　low　temperatures　(73.3%　discharge　capacity　retention　at-30　degrees　C).　Furthermore,　the　unique　solvated　sheath　structure　of　Tb-LSCE　also　regulates　the　interfacial　chemistry　and　uniformity　of　Li　depositing　behavior,　highlighted　by　the　outstanding　reversibility　of　Li-Li　cells　(a　long　lifespan　of　exceeding　1600　h　at　30　degrees　C　and　1100　h　at-30　degrees　C,　respectively)　and　Li-NCM523　cells　(80.7%,　160　cycles)　even　remarkably　stable　operation　within　50　cycles　(ultra-high　cathode　loading　of　19.7　mg　cm-2).　This　work　outlines　a　cheap　and　effective　electrolyte　design　solution　to　activate　the　potential　LMBs　under　practical　conditions,　especially　those　operated　under　cryogenic　environments.