Lithium solid electrolytes can potentially address two key limitations of the organic electrolytes used in today’s lithium-ion batteries, namely, their flammability and limited electrochemical stability. However, achieving a Li⁺ conductivity in the solid state comparable to existing liquid electrolytes (>1 mS cm^-1) is particularly challenging. In this work, we reveal a fundamental relationship between anion packing and ionic transport in fast Li-conducting materials and expose the desirable structural attributes of good Li-ion conductors. We find that an underlying body-centred cubic-like anion framework, which allows direct Li hops between adjacent tetrahedral sites, is most desirable for achieving high ionic conductivity, and that indeed this anion arrangement is present in several known fast Li-conducting materials and other fast ion conductors. These findings provide important insight towards the understanding of ionic transport in Li-ion conductors and serve as design principles for future discovery and design of improved electrolytes for Li-ion batteries.

Nature Materials 14, 1026–1031 (2015) doi:10.1038/nmat4369
Received 05 March 2015 Accepted 25 June 2015 Published online 17 August 2015

http://www.nature.com/nmat/journal/v14/n10/full/nmat4369.html

在锂离子电池中，相比于有机电解质，锂固态电解质有两方面的优势，一方面它有更低的易燃性，另一方面它有更好的电化学稳定性。不过，要使固态锂离子电导率达到液态电解质的水平（>1mS cm-1）是非常困难的。 Wang 等人揭示了快速 Li 传导材料中阴离子排列与离子传输之间的关系，以及利于锂离子传导的理想结构。他们发现，体心立方的离子骨架是获得高离子电导率的最理想结构，因为这种结构有利于锂离子在相邻的四面体间隙中跃迁。这些发现使科学家们更深入的认识锂离子导体中的离子传输过程，并为未来设计锂固态电解质指明了方向。（新材料在线）