1. Introduction
Nowadays, the depletion shortage of non-renewable natural fossil
resources and environmental damages has led to the development of
battery storage energy. Therein, energy storage through electrochemical
cells has been considered the most satisfactory solution due to its high
energy density, high power density, flexibility, and simplicity of
maintenance. Moreover, as shown as the state-of-the-art technology for
various applications, LIBs are required to show lightweight, long
lifespans, high specific capacity, and good retention capacity.
[1-4]
In recent years, the silicon-based anode has attracted more attention
because of its superior theoretical capacity of 3579
mAh.g-1. [5] However, the formation of
LixSiy alloy makes the silicon anode
suffers a high-volume expansion (over 280%), which leads to concerns
related to the safety and disconnection of electric contact, and then a
severe decrease of capacity after the first cycles. Therefore, silica
materials have been alternatives to develop silicon-based anodes owing
to less volume expansion and high capacity of 635.7
mAh.g-1 for LIBs. [6-7]
Although those materials overcome the weakness of silicon anode, their
low conductivity is one of the main reasons to prevent
commercialization. As a solution, a hybrid composite
SiO2/C was used to enhance battery performance. In
detail, the hard carbon in the SiO2 structure enhances
the ionic and electronic conduction and the kinetic migration of
Li+ inside the materials by creating a linking network
to boost electrons movements to convert SiO2 into Si and
co-products faster. [8-10] Nevertheless, SiO2/C
based as an anode suffers from significant active lithium loss, which
leads to low initial Coulombic efficiency in
Li-ion batteries. This phenomenon is caused by some
Li+ ions trapped in an anode structure. In detail, the
irreversible reaction and volume expansion create cracks inside the
electrode, which need a large amount of the electrolyte. As a result,
the thickness of the SEI layer increases after the first cycle, causing
a significant amount of Li+ ions to be trapped inside
the electrode by the SEI layer. [11-12]
To deal with this challenge, the pre-lithiation process was used to
compensate for the active lithium loss of the anode to enhance the
practical battery performance. [13-17] In this research, the two
common pre-lithiation methods were used, which include the direct
contact method (CM) using lithium foil and the half-cell electrochemical
method (EM). [18-22] These techniques were applied for the composite
anode SiO2/C, before matching in the full-cell with
NMC622, cathode. In CM, the time for anode directly contacted with
lithium was investigated. Meanwhile, regarding the electrochemical
method, the anode was assembled in half-cell and pre-lithiated at
various cycles to activate prior to the full-cell assembly. This study
hopefully brings new insights into selecting an appropriate approach to
successfully construct a high-performance lithium full-cell with
silica/carbon-based anode.