  Quantum repeater holds the promise for scalable long-distance quantum
communication. Towards a first quantum repeater based on memory-photon
entanglement, significant progresses have made in improving performances of the
building blocks. Further development is hindered by the difficulty of
integrating key capabilities such as long storage time and high memory
efficiency into a single system. Here we report an efficient light-matter
interface with sub-second lifetime by confining laser-cooled atoms with 3D
optical lattice and enhancing the atom-photon coupling with a ring cavity. An
initial retrieval efficiency of 76(5)% together with an 1/e lifetime of 0.22(1)
s have been achieved simultaneously, which already support sub-Hz entanglement
distribution up to 1000 km through quantum repeater. Together with an efficient
telecom interface and moderate multiplexing, our result may enable a first
quantum repeater system that beats direct transmission in the near future.
