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Biopolymers are an emerging class of novel materials with diverse applications and properties such as superior sustainability and tunability. Here, applications of biopolymers are described in the context of energy storage devices, namely lithium-based batteries, zinc-based batteries, and capacitors. Current demand for energy storage technologies calls for improved energy density, preserved performance overtime, and more sustainable end-of-life behavior. Lithium-based and zinc-based batteries often face anode corrosion from processes such as dendrite formation. Capacitors typically struggle with achieving functional energy density caused by an inability to efficiently charge and discharge. Both classes of energy storage need to be packaged with sustainable materials due to their potential leakages of toxic metals. In this review paper, recent progress in energy applications is described for biocompatible polymers such as silk, keratin, collagen, chitosan, cellulose, and agarose. Fabrication techniques are described for various components of the battery/capacitors including the electrode, electrolyte, and separators with biopolymers. Of these methods, incorporating the porosity found within various biopolymers is commonly used to maximize ion transport in the electrolyte and prevent dendrite formations in lithium-based, zinc-based batteries, and capacitors. Overall, integrating biopolymers in energy storage solutions poses a promising alternative that can theoretically match traditional energy sources while eliminating harmful consequences to the environment. 

Abstract Analogies are used to make abstract topics meaningful and more easily comprehensible to learners. Incorporating simple analogies into STEM classrooms is a fairly common practice, but the analogies are typically generated and explained by the instructor for the learners. We hypothesize that challenging learners to create complex, extended analogies themselves can promote integration of content knowledge and development of critical thinking skills, which are essential for deep learning, but are challenging to teach. In this qualitative study, college biology students (n = 30) were asked to construct a complex analogy about the flow of genetic information using a familiar item. One week later, participants constructed a second analogy about the same topic, but this time using a more challenging item. Twenty participants worked on the challenging analogy in pairs, while the other 10 worked alone. Analysis of the 50 interviews resulted in a novel‐scoring scheme, which measured both content knowledge (understanding of biology terms) and critical thinking (alignment of relationships between elements of the analogy). Most participants improved slightly due to practice, but they improved dramatically when working with a partner. The biggest gains were seen in critical thinking, not content knowledge. Having students construct complex, sophisticated analogies in pairs is a high‐impact practice that can help students develop their critical thinking skills, which are crucial in academic and professional settings. The discussion between partners likely requires students to justify their explanations and critique their partner's explanations, which are characteristics of critical thinking.