Novel PETEA-based grafted gel polymer electrolyte with excellent high-rate cycling performance for LiNi0.5Co0.2Mn0.3O2 lithium-ion batteries.

Due to the higher specific capacity and operating voltage platform of the ternary cathode material (LiCoxNiyMn1-x-yO2), it has a specific market application in the electric vehicle (EV) industry. Gel polymer electrolytes (GPEs) have proven to be an effective method of resolving this issue. As a result of its high conductivity and safety performance, pentaerythritol tetraacrylate (PETEA) is a promising gel polymer electrolyte. Butyl methacrylate (BMA) was successfully grafted onto PETEA to decrease its stiffness in this study. Surprisingly, after cycling for 100 cycles at a rate of 2 C, the cycle retention rate of the half-cell of NCM523/GPE/Li reached 63.9%, whereas the utilization of liquid electrolyte ceased to function normally. The successfully prepared PETEA-g-BMA GPE by in-situ thermal polymerization formed a three-dimensional network structure. The PETEA-g-BMA GPE effectively protected the structure of the cathode material during the lithium-ion charging and discharging process, inhibited the occurrence of side reactions, and minimized the risk of thermal runaway. The straightforward preparation process and low cost make industrial applications a possibility in the future.

Interface-Driven Pseudocapacitance Endowing Sandwiched CoSe2/N-Doped Carbon/TiO2 Microcubes with Ultra-Stable Sodium Storage and Long-Term Cycling Stability.

Cobalt diselenide (CoSe2) has drawn great concern as an anode material for sodium-ion batteries due to its considerable theoretical capacity. Nevertheless, the poor cycling stability and rate performance still impede its practical implantation. Here, CoSe2/nitrogen-doped carbon-skeleton hybrid microcubes with a TiO2 layer (denoted as TNC-CoSe2) are favorably prepared via a facile template-engaged strategy, in which a TiO2-coated Prussian blue analogue of Co3[Co(CN)6]2 is used as a new precursor accompanied with a selenization procedure. Such structures can concurrently boost ion and electron diffusion kinetics and inhibit the structural degradation during cycling through the close contact between the TiO2 layer and NC-CoSe2. Besides, this hybrid structure promotes the superior Na-ion intercalation pseudocapacitance due to the well-designed interfaces. The as-prepared TNC-CoSe2 microcubes exhibit a superior cycling capability (511 mA h g-1 at 0.2 A g-1 after 200 cycles) and long cycling life (456 mA h g-1 at 6.4 A g-1 for 6000 cycles with a retention of 92.7%). Coupled with a sodium vanadium fluorophosphate (Na3V2(PO4)2F3)@C cathode, this assembled full cell displays a specific capacity of 281 mA h g-1 at 0.2 A g-1 for 100 cycles. This work can be potentially used to improve other metal selenide-based anodes for rechargeable batteries.