Lithium Batteries

Nanotechnology of Positive Electrodes for Li-Ion Batteries

“…Thus, the long range order favors the formation of well-defined phases upon lithium insertion, while short range order modified deeply the charge-discharge profiles with absence of phase transition, i.e., formation of voltage plateaus [1]. In the following, we present several examples that emphasize the properties of nanomaterials used as cathodes in lithium batteries.…”

“…It means that, for instance, the Li x FePO 4 solid solution does not exist unless x is close to zero or close to 1. As a consequence, a rapid de-mixing occurs, and we are left with a two-phase system, namely, the larger values of α and β that result in the shrinking of the single-phase regions [1]. The corresponding voltage profile for the Li//LiFePO4 half-cell with nanosized cathode particles shown in Figure 7b displays a reduced voltage plateau over the concentration range α2 ≤ x ≤ β2 with α2 > α1 and β2 > β1.…”

“…The main drawback of transition-metal oxides used as positive electrode (cathode) materials in Li-ion batteries (LIBs) is their poor discharge rate capability due to low intrinsic electronic and ionic conductivity [1]. Thus, at high current densities, i.e., J > 1C rate (the rate is denoted C/n, where C is the theoretical cathode capacity and a full discharge occurs in n hours), the poor electrochemical performance is attributed to the slow electron transport of the material and the sluggish Li-ion kinetics within the grains.…”

Critical review on lithium-ion batteries: are they safe? Sustainable?

“…The positive electrodes Some of the most popular Li-ion technologies developed so far are reported in Table 1 taken from [2] with the acronym that will be used hereunder. The four first ones belong to the same family of lamellar compounds; the next one is the LiMn2O4 spinel; the last one is the olivine LiFePO4.The properties of these materials depend greatly on the crystal geometry, so that they must be analyzed separately.…”

“…That is why it is useful sometimes to write a critical review on the state-of-the-art of the lithium batteries and discuss what hope can we place in them in the near future. We have recently published a review on the state-of-the-art in the research on all the elements of the lithium-ion batteries in a book [2]. The purpose here is different, namely focus attention on the batteries that are already commercialized, and make a critical analysis to separate between what we can expect from them on a scientific basis, and what belongs to deceptive or misleading commercial advertising.…”