Page 27 - EngineerIt July 2021

ELECTRONICS

The difference between speaking about

lithium iron and lithium-ion, and why it

matters when describing batteries

By Felix von Bormann, REVOV co-founder and engineering director

ithium iron phosphate batteries - the ions flow from the cathode to the anode.
are part of a family of batteries Lithium-ion batteries come in many combinations
Lcalled lithium-ion batteries. of chemical makeup, which while remarkably
Specifying that a battery is a lithium iron, similar on the surface, vary in performance. The
or lithium iron phosphate, references selection of the active materials gives the batteries
the specific chemistry of the anode- their distinctive qualities. The cathode is what
cathode arrangement in the battery. differentiates each battery. For example, the lithium
This controls the envelope in which the cobalt dioxide is made with a LiCoO cathode while
2
battery behaves, which implies a host of the lithium iron phosphate battery is made with
characteristics which are important when LiFePO 4 as the cathode.
choosing a battery type and provider. This means that there is a technical distinction
Lithium iron phosphate batteries between lithium-ion and speaking about lithium iron. Felix von Bormann
(LiFePO4, or shortened to LFP) have Lithium-ion references the mode of electrical transfer
many advantages. We use lithium iron inside the battery, where ions travelling in the electrolyte are lithium. Lithium iron is a
phosphate batteries because they have subset of the family of lithium-ion batteries.
a great energy density and life cycle and Despite the characteristics they have in common (Li ion transfer), the different lithium-
a stable chemistry, all while maintaining ion systems and lithium iron batteries are different in terms of their stability, life span and
high thermal tolerance and resulting in a application. There are six main versions of lithium-ion batteries namely lithium cobalt oxide,
long life, at low costs. lithium manganese oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate,
lithium nickel cobalt aluminium oxide and lithium titanate.
How it works Without wishing to endorse any website, for those interested in taking the time to learn
Lithium-ion batteries are secondary cells all about batteries, an online resource called Battery University contains useful information,
created from layers of lithium sheets demystifying these important components in our collective future: batteries.
packed with an electrolyte. A lithium
battery is formed by four important
components, namely the cathode, anode,
electrolyte and a separator.
The cathode, a positive electrode,
determines the capacity and voltage of the
battery and is the source of lithium ions.
The anode, a negative electrode, stores
the lithium ions when the battery is charged
and enables the electric current to flow
through an external circuit. The electrolyte
is formed of salts, solvents and additives,
and serves as the channel of lithium ions
between the cathode and anode, while the
separator is the physical barrier that keeps
the cathode and anode apart.
The cathode is a metal oxide and the
anode consists of porous carbon matrix,
thus during discharge the ions flow from
the anode to the cathode through the
electrolyte and the separator; when
charging the battery the reverse happens

EngineerIT | July 2021 | 25