Growing concern regarding the impact of fossil fuels has led to demands for the development of green and renewable materials for advanced electrochemical energy storage devices. Biopolymers with unique hierarchical structures and physicochemical properties, serving as an appealing platform for the advancement of sustainable energy, have found widespread application in the gel electrolytes of supercapacitors. In this Review, we outline the structure and characteristics of various biopolymers, discuss the proposed mechanisms and assess the evaluation metrics of gel electrolytes in supercapacitor devices, and further analyze the roles of biopolymer materials in this context. The state-of-the-art electrochemical performance of biopolymer-based hydrogel electrolytes for supercapacitors and their multiple functionalities are summarized, while underscoring the current technical challenges and potential solutions. This Review is intended to offer a thorough overview of recent developments in biopolymer-based hydrogel electrolytes, highlighting research concerning green and sustainable energy storage devices and potential avenues for further development.

Continuous passive motion (CPM) is an adjunct therapy to the standard postoperative rehabilitation regimen of joint injuries. The capability of real-time monitoring actual bending angle of knee joints is highly desired for treatment strategies of personalized postoperative rehabilitation and telemedicine. Here we report an intelligent CPM system for personalized rehabilitation and telemedicine based on the flexible and versatile ionotronic that possesses impressive mechanical properties (2.56 MPa tensile strength; 11.63 MJ m⁻³ toughness), fast self-recovery ability (60 s) and broaden environmental tolerance (−60–45 °C). Especially, the ionotronic responds fast and shows stability for cyclic strain sensing, ensuring the detection of actual joint bending angle with high sensitivity and reliability. The intelligent CPM system assembled with this ionotronic and a wireless transmitter was constructed, opening up a horizon for developing digital intelligent medical that can remotely monitor the movement of hospitalized/at-home patients who use CPM for personalized postoperative rehabilitation.

Heterogeneous structures are ubiquitous in natural organisms. Native heterogeneous structures inspire many artificial structures that are playing important roles in modern society, while it is challenging to identify the relevant factors in forming these structures due to the complexity of living systems. Here, hybrid hydrogels consisting of flexible polymer networks with embedded stiff cellulose nanocrystals (CNCs) are considered an open system to simulate the generalized formation of heterogeneous core-sheath structures. As the result of the modified air drying process of hybrid hydrogels, the formation of heterogeneous core-sheath structure is found to be correlated to the relative evaporation speed. Specifically, the formation of such heterogeneity in xerogel fibers is found to be correlated with the divergence of Deborah number (De). During the transition of De from large to small values with accompanying morphologies, the turning point is around De = 1. The mechanism can be considered a relative humidity-dependent glass transition behavior. These unique heterogeneous structures play a key role in tuning water permeation and water sorption capacity. Insights into these aspects can prospectively contribute to a better understanding of the native heterogeneous structures for bionics design.

Continuous passive motion (CPM) has become an adjunct therapy to the standard postoperative rehabilitation regimen of joint injuries for a long time. However, the ability to in real-time monitor leg bearing capacity and actual bending angle of knee joints is highly desired for the treatment strategies of personalized postoperative rehabilitation and telemedicine. Here we report a novel intelligent CPM system for personalized rehabilitation and telemedicine based on the flexible and versatile ionotronic that possesses excellent mechanical properties and brilliant environmental tolerance. Especially, the corresponding ionotronic responds fastly and shows excellent cycling stability for strain sensing, ensuring the detection of actual joint bending angle with a high sensitivity and reliability. An intelligent CPM system assembled with this ionotronic and a wireless transmitter was constructed, opening up a new horizon for developing digital intelligent medical that can remotely monitor the movement of hospitalized/at-home patients who use CPM for personalized postoperative rehabilitation.