| In order to understand and solve the growing energy and ecological problems in modern society,teachers and students should be guided to combine classroom teaching with green chemistry.Green chemistry should not only be permeated into classroom teaching,but also be devoted to exploring green chemistry experiment cases suitable for senior high school students.Focusing on the basic knowledge of electrochemistry in Chapter 4 of the elective course of PEP,this paper introduces the frontier scientific research into teaching and develops four green chemistry research-oriented experiments suitable for senior high school students.The content of the case meets the requirements of the Basic Education Curriculum Reform Outline(Trial Implementation),and aims to cultivate students' core literacy and green chemistry literacy.The design of the experimental case is guided by the idea of green chemistry,the five-dimensional goal of core literacy and the concept of STEM education.Students' core literacy and green chemistry literacy can be cultivated by creating real situations.The development of laboratory experiment case based on research is divided into four stages,which are: identifying and familiarizing with research projects,preparing experiments,pilot experiments and feedback evaluation,and large-scale implementation.The implementation of the experimental case is as follows:(1)The past and present life of lithium-ion batteries.First,students learn the history,structure,composition,characteristics and working principle of lithium-ion batteries.Secondly,the working principles of lithium-sulfur batteries and lithium-air batteries were studied,and the students' understanding ability and knowledge transfer ability were fully exercised.Finally,students assemble lithium-ion batteries,light up light-emitting diodes,and summarize the relationship between electrolyte concentration and voltage: electrolyte concentration is proportional to voltage.(2)Students first learn the working principle,assembly and performance test methods(cyclic voltammetry and constant current charge and discharge)of electric double layer capacitors and Faraday quasi-capacitors.They then analyzed the cyclic voltammetry,specific capacitance,and energy density and concluded that the electric double layer capacitors have good cycle stability and the Faraday quasi-capacitors have higher specific capacitance and energy density.(3)On the basis of case 2,the students explored the effects of different electrolytes on the electrochemical performance of double-layer capacitors.Organic electrolyte can provide 3V voltage,but its cycle stability and specific capacitance are not high.The water electrolyte provides a higher voltage(1-1.4V),but it has better cycle stability and specific capacitance.(4)Preparation of a solid electrolyte conductive hydrogel.First,students learn the definition and characteristics of hydrogels by investigating hydrogel products in their lives and reading the literature.Then they plotted the classification mind map.Next,they designed and implemented anexperimental solution for conductive hydrogels.In the end,an independent learning system was established and a knowledge network related to chemistry and physics was established.Through classroom observation,after-class quizzes and the investigation and analysis of the students' recognition of experimental cases,it is concluded that the students' reaction is positive,they have great interest in the project,and show strong autonomy and creativity.Successful links between basic electrochemistry and scientific research enable students to have a deeper understanding of electrochemistry concepts and principles,and gain practical experience on clean energy storage devices.At the same time,it also exercises students' analytical ability,information integration ability,practical ability,etc.The most important thing is to enhance students' green chemistry literacy and core literacy. |
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