Li4Ti5O12 nanosheets assembled in tubular architecture for lithium storage

Abstract

Owing to their fantastic structural advantages of large surface area and shortened Li+/electron transport pathway, hierarchical tubular nano-/micro-materials have attracted much attention as the anodes used in lithium-ion batteries (LIBs). However, rational design and simple fabrication of hierarchical tubular structures assembled by non-particulate nanoscale building blocks still face many challenges. Herein, well-defined ultrathin Li4Ti5O12 nanosheet-assembled hierarchical tubes (LTONS-HTs) were synthesized through a one-step low-temperature hydrothermal lithiation procedure followed by topotactic transformation via thermal decomposition in air. It was proposed here that the formation of the hierarchical tubular structure was led by an inward dissolution and outward recrystallization mechanism. When tested as anode for LIBs, LTONS-HT manifests high rate capability (e.g. 156 mA h g−1 at 4 A g−1, and 154 mA h g−1 at 10 A g−1) and maintains an outstanding specific capacity of 128 mA h g−1 at 8 A g−1 after 1000 cycles. Moreover, LTONS-HTs is matched with the commercial cathode LiFePO4 to assemble a Li-matched full cell, which demonstrates good rate performance (58 mA h g−1 at 4 A g−1) and very stable energy-storage performance (a capacity retention of ∼80% after 300 cycles 2 A g−1). The superior electrochemical properties verify that the combination of the structural advantages of tubular architecture and ultrathin nanosheet can prompt the lithium insertion/extraction kinetics. Our work offers a new approach to the scalable and cost-effective synthesis of advanced hierarchical Li4Ti5O12 anodes for high-power LIBs.