Yasuhiko Kitamoto, Kiet Le Anh Cao, Phong Hoai Le, Oktaviardi Bityasmawan Abdillah, Ferry Iskandar, and Takashi Ogi*, A Sustainable Approach for Preparing Porous Carbon Spheres Derived from Kraft Lignin and Sodium Hydroxide as Highly Packed Thin Film Electrode Materials, Langmuir, 38, 3540?3552 (2022) 8 March 2022