We present the ternary phases Li
xVPn4 (Pn = P, As) as new materials for the negativeelectrode in lithium-ion batteries. Associated with a large variation of lithium content performula unit (3
x 7.5 for P and 3
x 11 for As), these materials show a higher specificcapacities in their first charge/discharge cycle than the graphite (550 mA·h/g for Pn = Pand 530 mA·h/g for Pn = As vs 372 m·Ah/g for
Cgr) and open new routes for the design ofnew types of rechargeable Li-ion batteries. High-temperature syntheses, X-ray diffractionanalyses, and first-principle electronic structure calculations give evidence of remarkablestability of the Li
xVPn
4 crystal structure upon various lithium compositions. Owing to ratherstrong covalent V-Pn bonds, the host matrixes behave as structurally stable networks ofweakly interacting tetrahedra, able to store (respectively, release) a large number ofadditional electrons (correlatively with the intercalation (respectively, deintercalation) ofLi
+ in the host matrix) into a nearly nonbonding Pn-Pn band. This leads to very weakvolumetric variations (<1%) of the unit cells upon cycling compared to what is usuallyobserved in the negative electrode materials such as alloy compounds. The cyclingperformances of the new, promising Li
xVPn
4/Li cells are currently under investigation.