In the race for better Li-ion batteries, research on anode materials is very intensive as there is a strong desire to find alternatives to carbonaceous negative electrodes. A large part of these studies is devoted to alloying reactions, which have been known for more than thirty years but that have regained great interest by downsizing particle sizes, moving to nano-textured/ nanostructured composites, or designing new electrode concepts. It is not the scope of this review to retrace twenty-five years of research, but rather to highlight recent advances that have been made in the use of Sn or Si-based electrodes together with the remaining challenges to be addressed and issues to be solved prior to such electrodes being commercially implemented in Li-ion cells.

Li-ion batteries have empowered consumer electronics and are now seen as the best choice to propel forward the development of eco-friendly (hybrid) electric vehicles. To enhance the energy density, an intensive search has been made for new polyanionic compounds that have a higher potential for the Fe²⁺/Fe³⁺ redox couple. Herein we push this potential to 3.90 V in a new polyanionic material that crystallizes in the triplite structure by substituting as little as 5 atomic per cent of Mn for Fe in Li(Fe(1-δ)Mn(δ))SO₄F. Not only is this the highest voltage reported so far for the Fe²⁺/Fe³⁺ redox couple, exceeding that of LiFePO₄ by 450 mV, but this new triplite phase is capable of reversibly releasing and reinserting 0.7-0.8 Li ions with a volume change of 0.6% (compared with 7 and 10% for LiFePO₄ and LiFeSO₄F respectively), to give a capacity of ~125 mA h g⁻¹.

Alpha-Fe(2)O(3) has been synthesized with an ordered mesoporous structure and crystalline walls that exhibit a near-single crystal-like order. The unique magnetic behavior of the material, distinct from bulk nanoparticles of alpha-Fe(2)O(3) or mesoporous Fe(2)O(3) with disordered walls, has been established. Magnetic susceptibility, Mössbauer, and neutron diffraction data show that the material possesses the same long-range magnetic order as bulk alpha-Fe(2)O(3), despite the wall thickness being less than the 8 nm limit below which magnetic ordering breaks down in nanoparticulate alpha-Fe(2)O(3), yet the Morin transition of bulk alpha-Fe(2)O(3) is absent. It is also shown by TEM, PXRD, and EXAFS that alpha-Fe(2)O(3) with the same ordered mesoporous structure but disordered walls contains small crystalline domains. Mössbauer and magnetic susceptibility data demonstrate that this material exhibits no long-range magnetic order but superparamagnetic behavior.