Nowadays, in the transition stage between the liquid electrolyte and solid electrolyte, the lean electrolyte strategy developed based on ceramic-polymer composite electrolytes (CPEs) has important practical significance to make up for their shortcomings and realize coordinated improvement of safety performance and electrochemical performance. However, the lean electrolyte CPE system is seriously limited by the contradiction between ion transport and swelling of polymer components in CPEs in practical applications. Polymers with high ionic conductivity tend to absorb the few liquid electrolytes and subsequently swell, resulting in reduced electrode wettability and electrical properties, while polymers that do not swell usually have poor ionic conductivity, reducing the intrinsic conductivity of CPEs. Herein, a binary solvophilic/solvophobic polymer network of CPEs is constructed under lean electrolyte condition. As a solvophilic segment, the urea-functionalized poly(propylene oxide) can not only improve the Li+ transport capacity but also form hydrogen bonds with the fluorine on the solvophobic poly(vinylidene fluoride-co-trifluoroethylene) (PVDF–TrFE) segment, thereby forming a hydrophobic composite network at the molecular scale. Then, the epoxidized Li1+xAlxTi2–x(PO4)3 (LATP) is further cross-linked with the urea amino groups on the polymer chain. This can significantly inhibit swelling and improve the ion transmission performance, endowing lithium-metal batteries with excellent electrochemical properties.
Hailong Yang,Hantian Lu,Yueyue Miao,Yang Cong,Yubin Ke,Jun Wang,Hua Yang,Jun Fu
Non-swelling super-tough polymer hydrogels have great potentials for stable applications in wet conditions. It has been challenging since most polymer hydrogels uptake water from the environment and swell, which deteriorates the mechanical strength and toughness. Here, we present multi-responsive non-swelling polymer hydrogels ( PHFGs ) by using amphiphilic triblock copolymer micelles as non-covalent crosslinkers. Pluronic F127 (or polyethylene oxide- block -polypropylene oxide- block -polyethylene oxide, PEO-PPO-PEO) (F-127) micelles are used as a prototype for the synthesis of micelle-crosslinked poly-(2-hydroxyethylene methacrylate) (PHEMA) hydrogels, without using any modification of F-127 or other crosslinkers. FT-IR and 1 H NMR studies provide first evidence that F-127 micelles form extensive hydrogen bonding and hydrophobic association with PHEMA chains. The non-covalent crosslinked hydrogels show a high fracture elongation about 460 %, a fracture strength about 240 kPa, and a fracture toughness about 660 kJ/m 3 . Negligible swelling is observed for the polymer hydrogels in aqueous solutions. The hydrogels are self-healable, and responsive to variations in pH or water content to change volume, shape, and transparency. Such multiple-responsive polymer hydrogels are utilized as smart switches and shape memory materials that are actuated by environmental stimuli in a controllable manner.
Zhongyuan Tian,Shilin Luo,Shangzhi Yue,Zheng Li,Dan Yang
Hydrogels have attracted increasing attention in wearable sensors, but preparing underwater hydrogel sensors with excellent anti-swelling and self-healing properties is still challenging. Herein, an anti-swelling and self-healing hydrogel is prepared by grafting poly(acrylic acid) with hydrophobic lauryl methacrylate, as well as constructing a second network and multiple molecular interactions (abbreviated as PALCF). The introduced hydrophobic long alkyl chains and the increased cross-linking density of the hydrogel result in a swelling ratio of only 0.04% after immersion in water for 15 days. Due to abundant metal coordination and hydrogen bonds, the PALCF hydrogel exhibits a high tensile stress of 0.60 MPa and a self-healing efficiency reaching 96.0% after self-healing at 60 °C for 2 min. Based on the piezoresistive effect, the PALCF hydrogel is directly used as an underwater strain sensor with a high sensitivity (GF = 2.24) to control underwater vehicles for rescue implementation. Furthermore, two self-powered triboelectric nanogenerator sensors with contact and non-contact models are constructed based on PALCF hydrogels for underwater communication, capable of sending out SOS messages and drowning alarms in emergency. The proposed underwater sensors with drowning warning and rescuing functions have the potential for use in drowning prevention, human–machine interfaces, and underwater communication system.
危险品化学品经营许可证（带存储）