development of advanced materials for supercapacitors, batteries, and water splitting for contributing to a better world

Ever-increasing demands for portable electronics along with the inevitable demand for clean renewable energy have considerably pushed the development of next-generation energy storage and conversion devices with the characteristics of a high capacity/capacitance, high energy, and high power, fast charging capability, and long cycling stability. as a remedy to these challenges and to build a better world, we have developed some advanced electrode materials for electrochemical energy storage and conversion devices. in one approach, we used a facile and scalable laser-scribing method to prepare graphene films and fabricate a multifunctional system [1]. the laser-scribed graphene (lsg) in the multifunctional integrated system not only serves as a substrate-free micro-supercapacitor (μsc), but also serves as a thin-film humidity sensor, a resistor, and a near field communication (nfc) antenna for internet-of-things (iot)-linked wireless communication with a smartphone. we also have reported a simple hydrothermal method for conjugation of thionine (th) and nile blue (nb) as positively charged and readily available planar aromatic redox dyes to graphene aerogel via π-π stacking interaction [2, 3]. this non-covalent conjugation method induced extra stability to the th(nb)-ga macromolecules and resulted in excellent structural stabilities and significantly higher supercapacitive performances. in another approach, we electrosynthesized an interpenetrating network of polyaniline and lignosulfonate (pani-ls) on carbon fibers as a high-performance supercapacitive energy storage material [4]. we also electrosynthesized a trilayer metal-organic framework (mof) in which fe, co, and ni layers are electrodeposited in a layer-by-layer (lbl) assembled method [5]. the lbl assembled mof displayed excellent energy storage performance as a cathode of a zinc-air battery that outperforms the commercial noble metal benchmarks and serves as a supercapacitive material as well. the trimetallic fe-co-ni mof also demonstrated excellent trifunctional electrocatalytic activities toward the hydrogen evolution reaction (her, ηj=10 = 116 mv), oxygen evolution reaction (oer, ηj=10 = 254 mv), and oxygen reduction reaction (orr, half-wave potential = 0.75 v vs. rhe). we also used layered-double hydroxides (ldh) and their composites with graphene-based materials for the development of a variety of energy storage and conversion devices [6, 7]. in a comprehensive review, we also surveyed the standard performance metrics of batteries and supercapacitors that would help the researchers of the energy storage community to evaluate the energy storage devices with well-established criteria [8]. we hope these intriguing approaches will inspire further studies and paves the way toward a more secure energy future.