In terms of sustainable development and environmental issues, the use of efficient storage systems is an increasingly critical point. The world has undergone a great technological revolution in the past 20 years led by lithium ion batteries, due to their high energy density. However, in order to meet the energy demand of our modern life, a new generation of lithium batteries, more powerful, efficient and cheaper, is desirable. Depending on the problem to be addressed, it is useful to model the system at different scales. For example, while first-principles calculations may be useful to predict equilibrium potentials, semiempirical potentials along with molecular dynamics or Monte Carlo simulations may be applied to understand collective phenomena.  In the present work we show in terms accessible to experimentalists how the use of different simulations tools may be helpful to analyze different aspects of lithium storage materials. The topics to be addressed in the present work are:

• Use of first- principles calculations to optimize the stability of Si-Graphite nanostructures.
• Application of Monte Carlo simulations to get thermodynamic information on the storage of Li ions into graphite.
• Optimization of composites using coarse-grained models.