Some designs (silicon, germanium and transition metal oxides), variations of the lithium-ion battery have been announced, although none are commercially available.
This volume expansion occurs anisotropically, caused by crack propagation immediately following a moving lithiation front.
[4] Doping impurities, such as phorphorus or boron, into the nanowire anode can also improve performance by increasing the conductivity.
[5] An anode using germanium nanowire was claimed to have the ability to increase the energy density and cycle durability of lithium-ion batteries.
Like silicon, germanium has a high theoretical capacity (1600 mAh g-1), expands during charging, and disintegrates after a small number of cycles.
This performance was attributed to a restructuring of the nanowires that occurs within the first 100 cycles to form a mechanically robust, continuously porous network.
Due to largely increased surface area, this cell was able to deliver an almost constant capacity of about 190 mAh g−1 even after 1,000 cycles.
MnO2 has always been a good candidate for electrode materials due to its high energy capacity, non-toxicity and cost effectiveness.
To counteract this effect during operation cycle, scientists recently proposed the idea of producing a Li-enriched MnO2 nanowire with a nominal stoichiometry of Li2MnO3 as anode materials for LIB.
This new proposed anode materials enable the battery cell to reach an energy capacity of 1279 mAh g−1 at current density of 500 mA even after 500 cycles.
At operation, Co3O4 promotes a more efficient ionic transport, while Fe2O3 enhances the theoretical capacity of the cell by increasing the surface area.