A phase inversion based sponge-like polysulfonamide/SiO 2 composite separator for high performance lithium-ion batteries

Novel bacterial cellulose nanocrystals/polyether block amide microporous membranes as separators for lithium-ion batteries

Bacterial cellulose nanocrystals (BCNCs) were extracted from nata de coco waste and underwent sulphuric acid (H₂SO₄) hydrolysis for use as a reinforcement giving thermal and dimensional stability to polyether block amide (PEBAX) as a polymer matrix for the fabrication of BCNCs/PEBAX microporous membranes. The H₂SO₄-hydrolysis of BCNCs yielded rod-like/needle-like BCNCs and negatively charged surfaces, resulting from the generated surface sulfate groups on the bacterial cellulose (BC), which may be competent for numerous applications. The non-solvent induced phase separating (NIPS) and subsequent film casting methods were used to prepare the BCNCs/PEBAX microporous membranes. The obtained films were characterized with regards to their structure in terms of the content of crystalline phases, as well as their ionic transport and performance at elevated temperatures. The presence of the BCNCs fillers resulted in a good thermal and dimensional stability up to 150 °C and correlated with no membrane shrinkage. For NIPS membranes, the formation of a rigid cellulosic network within the matrix was emphasized and attributed to the thermal stabilization at temperatures above the melting temperature. In addition, the wettability, ionic conductivity, and thermal stability were investigated in BCNCs/PEBAX membranes filled with different amounts of BCNCs. Thus, the BCNCs/PEBAX membranes derived via NIPS had a remarkably good ionic conductivity, within the range of 10^-2-10^-3 S/cm, with up to 56.8% porosity. Such porous membranes are considered as an important and interesting candidate for the replacement of the commercial polyolefin-based microporous separator in lithium-ion batteries due to their superior electrochemical performances and the observed reinforcement effect.

Recent Development in Separators for High-Temperature Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are promising energy storage devices for integrating renewable resources and high power applications, owing to their high energy density, light weight, high flexibility, slow self-discharge rate, high rate charging capability, and long battery life. LIBs work efficiently at ambient temperatures, however, at high-temperatures, they cause serious issues due to the thermal fluctuation inside batteries during operation. The separator is a key component of batteries and is crucial for the sustainability of LIBs at high-temperatures. The high thermal stability with minimum thermal shrinkage and robust mechanical strength are the prime requirements along with high porosity, ionic conductivity, and electrolyte uptake for highly efficient high-temperature LIBs. This Review deals with the recent studies and developments in separator technologies for high-temperature LIBs with respect to their structural layered formation. The recent progress in monolayer and multilayer separators along with the developed preparation methodologies is discussed in detail. Future challenges and directions toward the advancement in separator technology are also discussed for achieving remarkable performance of separators in a high-temperature environment.

A Review on Inorganic Nanoparticles Modified Composite Membranes for Lithium-Ion Batteries: Recent Progress and Prospects

Separators with high porosity, mechanical robustness, high ion conductivity, thin structure, excellent thermal stability, high electrolyte uptake and high retention capacity is today's burning research topic. These characteristics are not easily achieved by using single polymer separators. Inorganic nanoparticle use is one of the efforts to achieve these attributes and it has taken its place in recent research. The inorganic nanoparticles not only improve the physical characteristics of the separator but also keep it from dendrite problems, which enhance its shelf life. In this article, use of inorganic particles for lithium-ion battery membrane modification is discussed in detail and composite membranes with three main types including inorganic particle-coated composite membranes, inorganic particle-filled composite membranes and inorganic particle-filled non-woven mates are described. The possible advantages of inorganic particles application on membrane morphology, different techniques and modification methods for improving particle performance in the composite membrane, future prospects and better applications of ceramic nanoparticles and improvements in these composite membranes are also highlighted. In short, the contents of this review provide a fruitful source for further study and the development of new lithium-ion battery membranes with improved mechanical stability, chemical inertness and better electrochemical properties.