**1.2 Coating or combining TiO2 with carbonaceous materials**

To improve the electrochemical performance of TiO2 materials, carbon coating was used in order to reduce the charge transfer resistance, improve the Li<sup>+</sup> , buffer the large volume changes during lithium insertion/extraction, enhance electron transport and prevent the aggregation of active materials [9–22, 23]. Xia *et al.* have reported a carbon-coated TiO2 anode material with an enhanced electronic conductivity and a low volume expansion during prolonged cycling [24]. In a different study, chemical vapor deposition was used to synthesize TiO2/CNTs composites, exhibiting a high specific capacity and a long-term cycling stability [25]. This study demonstrated that the enhanced electrochemical performance of this material is due to the structural stability and the efficient conductive network of the TiO2 particles offered by CNTs. Etacheri *et al.* mixed TiO2 with graphene and the synthetized hybrid materials exhibited a high specific capacity, an improved capacity retention and a good rate capability, in comparison with the physical mixture of TiO2 and reduced graphene oxide [26].

#### **1.3 Selective doping with mono and heteroatoms**

To improve the intrinsic conductivity and form more open channels and active sites for Li<sup>+</sup> transport, doping with cationic or anionic dopants has been shown to be advantageous [27, 28]. Liu *et al.* evaluated the performance of Ti3+ doped TiO2 nanotube arrays as anode material for LIBs showing an enhanced lithium ion storage performance with an initial discharge capacity of 101 mAh g−1 at a high current density of 10 A g−1 [29]. Furthermore, Sn-doped TiO2 nanotubes were synthetized by Kyeremateng and coworkers delivering higher capacity values compared to non-doped TiO2 nanotubes [30]. Otherwise, TiO2 materials with improved specific capacities were synthesized, by other researchers, using B and N and doping elements [31, 32].

In the following chapter, simple and cost-efficient strategies for the preparation of TiO2 nanoparticles as anode material for LIBs are discussed. These strategies consist of using the Sol–Gel method, with a sodium alginate biopolymer as a templating agent, and studying the influence of the calcination temperature and the phosphorus doping on the structural, the morphological, the textural and the electrochemical properties of TiO2 material.
