Li₂NaV₂(PO₄)₃/Hard Carbon Nanocomposite Cathodes for High‐Performance Li‐ and Na‐Ion Batteries

Abstract

Abstract Rhombohedral Li 2 NaV 2 (PO 4 ) 3 (R‐LNVP) is a promising cathode for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs), owing to its open framework with large ion‐transport tunnels and high electrochemical stability. In this work, a new type of nanocomposite was synthesized by using waste lignins as the structure template and the sources of Na and hard carbon, in which the rhombohedral Li 2 NaV 2 (PO 4 ) 3 (R‐LNVP) nanoparticles (ca. 15–30 nm) are homogeneously embedded in the hard carbon networks. The influences ofpapermaking black liquor (PBL) on the structure and electrochemical properties of the nanocomposites were investigated. The nanocomposite cathode exhibits high reversible capacities, that is, 137.2 mAh g −1 at 0.1 C in LIBs, but also 91.04 mAh g −1 at 0.2 C in SIBs. Moreover, the original fluid consumption rate of PBL reaches 2.36 L per kilogram of the nanocomposite through the synthesis process, which reduces the load of PBL to environment.