Research progress on TiO2-modified lithium and lithium-sulfur battery separator materials

Abstract

With the increasing promotion of new energy vehicles and the rapid popularization of digital electronic products, there is a growing demand for lithium-ion and lithium-sulfur batteries. These batteries have gained widespread attention due to their excellent electrochemical performance. However, with the continued demand for high-power applications in new energy vehicles and digital electronics, the safety and stability of the batteries have become critical. TiO2 is commonly utilized in battery separators owing to its capacity to enhance the thermal stability, mechanical properties, and electrochemical stability. It can inhibit the “shuttle effect” of polysulphides in lithium-sulfur batteries through physical and chemical methods to improve the cycling performance of lithium-sulfur batteries. This review will outline three methods for modifying TiO2 separators: blending (utilizing electrostatic spinning and phase conversion), coating (involving the coating method, immersion fabrication method, and vacuum filtration method), and grafting. Finally, the prospective evolution of battery separators and the concomitant challenges they confront will be contemplated.

Full text

Vol.:(0123456789)
Ionics
https://doi.org/10.1007/s11581-024-05595-1
REVIEW
Research progress on TiO2‑modified lithium andlithium‑sulfur battery
separator materials
YapengLi1· YingxueSun1· ShuaitianJia1· ChaohuaSong1· ZanChen2· YinhuiLi1
Received: 24 January 2024 / Revised: 8 May 2024 / Accepted: 20 May 2024
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024
Abstract
With the increasing promotion of new energy vehicles and the rapid popularization of digital electronic products, there is a
growing demand for lithium-ion and lithium-sulfur batteries. These batteries have gained widespread attention due to their
excellent electrochemical performance. However, with the continued demand for high-power applications in new energy
vehicles and digital electronics, the safety and stability of the batteries have become critical. TiO2 is commonly utilized in
battery separators owing to its capacity to enhance the thermal stability, mechanical properties, and electrochemical stabil-
ity. It can inhibit the “shuttle effect” of polysulphides in lithium-sulfur batteries through physical and chemical methods
to improve the cycling performance of lithium-sulfur batteries. This review will outline three methods for modifying TiO2
separators: blending (utilizing electrostatic spinning and phase conversion), coating (involving the coating method, immer-
sion fabrication method, and vacuum filtration method), and grafting. Finally, the prospective evolution of battery separators
and the concomitant challenges they confront will be contemplated.
Keywords TiO2· Separators· Electrochemical properties· Modification· Lithium-ion batteries· Lithium-sulfur batteries
Introduction
Lithium-ion batteries comprise cathode materials, electro-
lytes, separators, and anode materials. The charging and
discharging processes are driven by the reciprocal shuttling
of lithium ions between the cathode and anode. During
charging, the cathode releases lithium ions, which traverse
the separator to reach the anode. Graphite, often used as
the anode material, has a layered carbon structure. Lith-
ium ions intercalate within these carbon layers; the more
ions it can accommodate, the higher the charge capacity.
In the discharge phase, this process reverses: lithium ions
migrate from the anode through the separator to the cath-
ode. Electrons concurrently flow from the external circuit
to the cathode, where they recombine with the lithium ions.
Such batteries offer salient benefits like prolonged cycle
life, minimal self-discharge, exceptional energy density, and
reduced weight [1]. They have found utility in diverse appli-
cations, from portable devices and mid-scale power systems
to expansive energy storage solutions [2].
Lithium-sulfur batteries primarily feature sulfur cathode
materials, separator, organic electrolytes, and lithium metal
anode materials [3]. During discharge, the lithium metal at
the anode oxidizes, relinquishing lithium ions and electrons.
These ions and electrons migrate to the sulfur cathode via
the electrolyte and external circuit, respectively. At the cath-
ode, sulfur is reduced by assimilating the lithium ions and
electrons, forming lithium sulfide (Li2S). Conversely, during
charging, Li2S dissociates back into Li and S [4, 5]. These
batteries offer significant advantages in terms of theoretical
energy density, material capacity, and raw material afford-
ability [6].
As depicted in Fig.1 which is the operational schemat-
ics of lithium-ion and lithium-sulfur batteries. A pivotal
component in these energy storage systems is the separator.
This critical element serves a dual purpose: it prevents direct
contact between the cathode and anode, mitigating short-
circuit risks, while simultaneously facilitating the migra-
tion of lithium ions [8–11]. The separator’s properties, as a
microporous membrane, directly impact ionic conductivity
* Yinhui Li
liyinhui@hebut.edu.cn
1 School ofChemical Engineering andTechnology, Hebei
University ofTechnology, Tianjin300400, P.R.China
2 Key Laboratory ofMembrane andMembrane Process,
China National Offshore Oil Corporation Tianjin Chemical
Research & Design Institute, Tianjin300131, P.R.China
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