VPO5: An all-climate lithium-storage material

Abstract

Battery electric vehicles (BEVs) are very popular nowadays. However, the current lithium-ion batteries (LIBs) for BEVs suffer from unsatisfactory electrochemical performance at low and high temperatures, limiting the use of BEVs in cold and hot situations. It is highly desirable but very challenge to explore all-climate Li+-storage materials. Herein, we explore VPO5 with a rich vanadium-valence variation and special crystal structure as an all-climate anode material with comprehensively good electrochemical performance. In its structure, electrochemical active VO6-octahedron chains are linked by inactive PO4 tetrahedra, not only generating large-sized channels for fast Li+ transport/storage but also enabling a maximum volume variation of only ∼0.6% during lithiation/delithiation. Additionally, the volume variation (maximum 9.7%) from the small amount (<30 wt.%) of the new LiVPO5 phase emerged after initial lithiation can be buffered by the large amount of “zero-strain” VPO5. Consequently, at 25 // −20 // 60 °C, VPO5 delivers a large reversible capacity of 246 // 181 // 334 mAh g−1 with a safe working potential of 0.74 // 0.69 // 0.77 V vs. Li/Li+ at 0.1C, high rate performance with 128 // 85 // 127 mAh g−1 at 10C // 2C // 10C, and good cyclability with capacity retention of 100.1% // 109.4% // 151.4% at 10C // 2C // 10C over 10,000 // 3000 // 1000 cycles within 0.2–3.0 V. These desirable electrochemical data from low to high temperatures suggest that VPO5 is a promising anode material for all-climate LIBs used in BEVs.