Ultra-Thin Mesoporous LiV3O8 Nanosheet with Exceptionally Large Specific Area for Fast and Reversible Li Storage in Lithium-Ion Battery Cathode

Abstract

LiV3O8 is considered as a promising cathode material for lithium-ion batteries (LIBs) because of its high specific capacity and good safety. However, the poor cycling stability and low rate capability of LiV3O8 electrode seriously hinder its application in long lifespan and high power LIBs. In the present work, an ultra-thin mesoporous LiV3O8 nanosheet is synthesized on the basis of efficient reduction-oxidation and freeze-dried strategy. The mesoporous nanosheet with a very small thickness of about 1.36 nm has an exceptionally large surface area of 397 m2 g−1 (8–20 times of LiV3O8 reported). The electrochemical test results indicate that the nanosheet cathode can deliver a reversible capacity of 301 mA h g−1 at current density of 100 mA g−1 in the potential range of 2.0–4.0 V and retain 87.1% of the starting discharge capacity after 550 discharge/charge cycles at 2000 mA g−1. The excellent lithium storage performances are ascribed to its unique flexible ultra-thin mesoporous nanosheet structure, which can increase the surface pseudocapacitive lithium storage, reduce the charge transfer resistance, improve the diffusion coefficient of lithium ion, and accommodate the volume changes of LiV3O8 in the discharge-charge processes. These results demonstrate a great potential of ultra-thin mesoporous LiV3O8 nanosheet for large capacity, long life and high power LIBs.