The　electrolyte　in　lithium-metal　batteries　(LMBs)　plays　a　pivotal　role　in　stabilizing　the　surface　of　the　lithium　metal　anode　(LMA)　and　high-voltage　cathode.　However,　currently　widely　studied　ether-based　electrolytes,　although　it　has　good　compatibility　with　LMA　due　to　their　lower　reactivity,　are　facing　significant　challenges　related　to　poor　oxidation　resistance　and　cathode/electrolyte　interface　(CEI)　instability　when　combined　with　the　high-voltage　cathode,　particularly　at　elevated　temperatures.　Therefore,　there　is　an　urgent　need　to　design　advanced　electrolytes　capable　of　maintaining　high　stability　under　high-voltage　and　high-temperature　conditions.　Here,　we　have　developed　an　ultra-stable　localized　high-concentration　electrolyte　(LHCE)　by　introducing　triethylene　glycol　dimethyl　ether　(TG),　which　exhibits　strong　solvation　ability.　Computational　and　experimental　results　demonstrate　that　the　designed　TG-based　dilute　high-concentration　electrolyte　(TG-DHCE)　possesses　a　stable　solvation　structure,　high　oxidation　resistance,　and　thermal　stability,　making　it　ideal　for　LMBs.　Furthermore,　the　unique　solvation　structure　of　TG-DHCE　promotes　the　preferential　decomposition　of　anions　while　facilitating　the　formation　of　stable,　inorganic-rich　electrode/electrolyte　interfaces　on　the　anode　and　cathode.　Consequently,　equipped　with　TG-DHCE,　Li||Li　cells　(more　than　1600　h)　and　Li||NCM523　cells　(80.6%,　250　cycles)　show　superior　stability　and　also　demonstrate　remarkable　performance　even　at　elevated　temperatures　(60　°C).　Additionally,　under　the　harsh　conditions　of　ultrahigh　loading　NCM523　cathode　(19.7　mg/cm2)　and　limited　Li　reservoir　(twice　excess　Li　was　deposited　on　Cu,　Li@Cu)　(N/P　=　2),　Li@Cu||NCM523　cells　still　maintain　stable　operation.　This　work　pioneers　a　new　path　by　choosing　strongly　solvating　solvents,　effectively　enhancing　the　cycle　life　of　LMBs　under　high-voltage　and　high-temperature　conditions.　©　2024