Achieving　a　high　Li+　transference　number　is　an　effective　strategy　to　inhibit　the　nucleation　of　lithium　dendrites　on　the　metal　anode　according　to　classical　Sand＇s　time　principle.　However,　improving　the　Li+　transference　number　usually　causes　aloss　of　ionic　conductivity　of　lithium　metal　batteries.　Here,　inspired　by　biological　ion　channels　tuning　ion　transport,　an　electronegative　nanochannels　separator　is　developed　to　accelerate　Li+　transport　for　enabling　dendrite-free　and　high-rate　lithium　metal　anodes.　Benefiting　from　selective　and　fast　Li+　transport,　the　electronegative　nanochannels　separator　can　simultaneously　achieve　high　Li+　transference　number　(0.77)　and　high　Li+　conductivity　(1.36　mS　cm(-2))　within　a　liquid　lithium　metal　battery.　Such　an　optimization　of　Li+　transport　dynamics　can　significantly　prolong　the　nucleation　time　of　lithium　dendrite　and　thus　effectively　suppress　dendritic　growth,　which　contributes　to　an　extremely　stable　Li　plating/stripping　cycling　for　over　2000　h　at　a　high　current　density　of　5　mA　cm(-2).　When　assembled　into　lithium　metal　batteries,　the　electronegative　nanochannels　separator　enables　superior　comprehensive　electrochemical　performance　compared　with　the　commercial　polyolefin　one.　This　work　provides　new　insights　into　the　design　of　functional　separators　toward　dendrite-free　and　high-rate　liquid　lithium　metal　batteries.