All wood supercapacitor Source Energy Environ Sci 2017

All wood supercapacitor Source: Energy Environ. Sci. , 2017, 10, 538545 Wood: as a new energy storage material Jingyi Liu (China) Faculty of Science and Forestry UEF// University of Eastern Finland jingyliu@uef. fi

1. Background Why we focus on energy storage? ▶ Energy crisis ▶ Environmental deterioration Why we choose wood? ▶ Rich in resources ▶ Natural channels Renewable High carbon content Biodegradable 2

2. Solid wood based energy storage Preparation Production process Wood Carbonization Carbonized wood Activating and loading active ingredients Wood Activating and loading active ingredients Precursor Physical activation Chemical activation Carbonization Electrode Loading active ingredient: Molten metal, metal ions, compounds, etc. 3

• . 2. Solid wood based energy storage Examples ▶ Pure carbonized wood ▶ Doping other elements ▶Molten metal Lithium-carbonized wood electrode. The cycle performance is excellent, the growth of metal 辛福恩. 陕西师范 大学, 2018. dendrite is inhibited, and the safety is improved. Fe. OOH Nanosheets New Journal of Chemistry, 2019, 43: 3649 -3652. Proc Natl Acad Sci U. S. A 2017, 114(14): 3584 -3589. Doping nitrogen 4

2. Solid wood based energy storage Solid wood-based materials can be used to assemble all wood supercapacitors Anode ---- Carbonized wood Diaphragm ---- Thin wood film Diaphragm ---- Cellulose paper Cathode ---- Mn. O 2@WC Cathode ---- Co(OH)2@CW Energy Environ. Sci. , 2017, 10, 538 -545 Advanced Functional Materials. 2018(9): 1806207. Advantages 1. High energy density and safety : 2. Completely green and environmentally friendly 3. Don’t cause environmental pollution. 5

3. Lignocellulose based energy storage We use! Wood fiber obtained by hot milling Purified wood fiber ▲ Single fiber ▲Fiber aggregates energy storage 6

3. Lignocellulose based energy storage Single fiber energy storage ▲ Characteristics : 1. Easy to modify 2. Surface active substances are easily exposed 3. The compound active substance is uniform 4. Production progress complex ACS applied materials & interfaces, 2017, 9(17): 14801 -14807. Energy Environ. Sci. , 2014, 7, 2670 Jiang separated the fiber bundles into individual fibers and compounded Mn. O 2 on each carbon fiber. Luo made sulfur-carbon cathode by compounding sulfur with single carbonized wood fiber. 7

3. Lignocellulose based energy storage Fiber aggregates energy storage ▲ Characteristics : 1. The compound active substance is not uniform. 2. The preparation is not hard. Journal of Applied Polymer. 2018(13), 47282. 3. The product is flexible and Aneeqa made wood fiber and polyaniline suitable for making paper-based coating (LC/PANI) paper-based electrode and electrode. polypyrrole coating(LC/PPY) paper-based electrode. 8

4. Cellulose nanofiber energy storage Introduction Nano cellulose colloid Nano cellulose(SEM) Characteristic ▲ Structure: winding network structure, high aspect ratio, more fine than other biomass cellulose ▲ Ingredients: high carbon content, active hydroxyl groups on the surface, easy to be chemically modified and compounded by active materials 9

4. Cellulose nanofiber energy storage Examples ▲Pure nanofibers ▲ Nanofiber membrane ▲ All nanofibers Luo directly carbonized cellulose nanofibers into sodium ion electrodes. Jabbour used nanofibers to make Li. Fe. PO 4 -CNF paper cathodes. Anode ----Carbon nanofibers Diaphragm ----Cellulose nanofibers Cathode ----Carbon nanofibers Compound Ni. Co 2 O 4 Journal of Materials Chemistry A, 2013(13): 10662 -10666. All paper battery Cellulose, 2013, 20 (1): 571 -582. ACS applied materials & interfaces, 2019. 11(6): 5919 -5927. 11

5. Summary 1. Improve the electrode activity, develop new activator and optimize the original activator. 2. Develop more all wood supercapacitors. 3. Develop more and better paper-based electrodes. 4. Simplify the production process, and reduce the cost. UEF// University of Eastern Finland jingyliu@uef. fi