Three-dimensional hierarchical walnut kernel shape conducting polymer as water soluble binder for lithium-ion battery

Cellulose sulfate lithium as a conductive binder for LiFePO4 cathode with long cycle life

Polysaccharides can be potential binders for lithium-ion batteries due to their strong adhesion through numerous hydroxyl groups. As a novel waterborne lithiated polysaccharide derivative, cellulose sulfate lithium (CSL) is successfully synthesized and used as the binder for LiFePO₄ (LFP) cathode. The chemical structure of CSL is verified by FTIR-ATR, XRD, C¹³-NMR, GPC, EA, ICP and TGA. Compared to LFP cathode using polyvinylidene difluoride binder, electrochemical measurements show that the LFP cathode using CSL (LFP-CSL) has lower polarization and better rate performance owing to higher lithium-ion conductivity of CSL. The result of morphological analysis indicates that CSL binder can maintain an integrated LFP cathode structure during hundreds of cycles. As a result, the LFP-CSL cathode exhibits a discharge capacity of 133.4 mAh g^-1 and maintains remarkable cycle stability with retention of 93.1 % after 300 cycles at 1C. These findings provide novel insights into the rational design of the binders for the LFP cathode.

Ultrasonic helical coil electrochemical reactor for simultaneous electrolysis-sonification-electrochemical polymerization, and applications for pollen cleaning

Electrochemical polymerization of aniline by a combination of ultrasonic waves and electrolysis of water was performed. This method involves three processes: 1) creation of O₂ micro bubbles produced by electrolysis of water on the anode side, 2) depolarization of the bubbles at the electrode surface via mechanical vibration using ultrasonic waves to diffuse ions in the electrolyte solution, and 3) progression of direct current (DC) electrochemical polymerization to yield a conductive polymer with fine pores on the surface. The diameter of the pores is on the micrometer scale and is similar in size to pollens. The combination of the electronic function of the conductive polymer and porous polymer surface can be applied as a method to collect allergens such as dust and flower pollens. Electrical adsorption and desorption of pollen was conducted with the porous polyaniline synthesized using a micro-bubble sonic-electrochemical preparation.

Rational Design of Effective Binders for LiFePO4 Cathodes

Polymer binders are critical auxiliary additives to Li-ion batteries that provide adhesion and cohesion for electrodes to maintain conductive networks upon charge/discharge processes. Therefore, polymer binders become interconnected electrode structures affecting electrochemical performances, especially in LiFePO4 cathodes with one-dimensional Li+ channels. In this paper, recent improvements in the polymer binders used in the LiFePO4 cathodes of Li-ion batteries are reviewed in terms of structural design, synthetic methods, and working mechanisms. The polymer binders were classified into three types depending on their effects on the performances of LiFePO4 cathodes. The first consisted of PVDF and related composites, and the second relied on waterborne and conductive binders. Profound insights into the ability of binder structures to enhance cathode performance were discovered. Overcoming the bottleneck shortage originating from olivine structure LiFePO4 using efficient polymer structures is discussed. We forecast design principles for the polymer binders used in the high-performance LiFePO4 cathodes of Li-ion batteries. Finally, perspectives on the application of future binder designs for electrodes with poor conductivity are presented to provide possible design directions for chemical structures.

A novel zwitterionic polymer binder with enhanced ionic conductivity for water-processable LiFePO4 cathodes

The structure of rich Li⁺ and zwitterions in LZI chains benefits the Li⁺ transport at the interfaces between the LZI and cathodes.