Green Strategy to Single Crystalline Anatase TiO2 Nanosheets with Dominant (001) Facets and Its Lithiation Study toward Sustainable Cobalt-Free Lithium Ion Full Battery

Abstract

A green hydrothermal strategy starting from the Ti powders was developed to synthesis a new kind of well dispersed anatase TiO2 nanosheets (TNSTs) with dominant (001) facets, successfully avoiding using the HF by choosing the safe substitutes of LiF powder. In contrast to traditional approaches targeting TiO2 with dominant crystal facets, the strategy presented herein is more convenient, environment friendly and available for industrial production. As a unique structured anode applied in lithium ion battery, the TNSTs could exhibit an extremely high capacity around 215 mAh g(-1) at the current density of 100 mA CI and preserved capacity over 140 mAh g(-1) enduring 200 cycles at 400 mA g(-1). As a further step toward commercialization, a model of lithiating TiO, was built for the first time and analyzed by the electrochemical characterizations, and full batteries employing lithiated TNSTs as carbon-free anode versus spinel LiNixMn2-xO4 (x = 0, 0.5) cathode were configured. The full batteries of TNSTs/LiMn2O4 and TNSTs/LiNiO5Mn1.5O4 have the sustainable advantage of cost-effective and cobalt-free characteristics, and particularly they demonstrated high energy densities of 497 and 580 Wh kg(anode)(-1) (i.e., 276 and 341 Wh kg(cathode)(-1)) with stable capacity retentions of 95% and 99% respectively over 100 cycles. Besides the intriguing performance in batteries, the versatile synthetic strategy and unique characteristics of TNSTs may promise other attracting applications in the fields of photoreaction, electro-catalyst, electrochemistry, interfacial adsorption photovoltaic devices etc.