Peroxodisulphuric acid synthesis in a flow electrolyser and its potential utilisation for black mass leaching
Tazhibayeva A. Tanash A. Zhigalenok Y. Abdimomyn S. Malik S. Zhumadil K. Nechipurenko S. Malchik F.
2025Royal Society of Chemistry
RSC Advances
2025#15Issue 5042450 - 42459 pp.
This study demonstrates the electrochemical synthesis of peroxodisulfuric acid (H2S2O8) in a coaxial flow-type electrolyser. It evaluates its potential as a leaching agent for the black mass from spent lithium-ion batteries. The optimised synthesis (conditions: flow rate, current density) achieved high concentrations of (H2S2O8) (≈180 g dm−3) at a specific energy consumption of nearly 1.5 Wh g−1. The leaching performance of H2S2O8 was compared with that of conventional systems, including aqua regia and 2 M H2SO4 + H2O2. While aqua regia completely dissolved the NMC phase, and the H2SO4/H2O2 mixture ensured nearly full transition metal leaching, H2S2O8 leaching resulted in only partial dissolution of Ni (≈61%), Co (≈61%), and Mn (≈5%). However, lithium was fully extracted (≈99.6%) due to dual dissolution from residual electrolyte salts and chemical deintercalation from the cathode lattice. Mechanistic analysis using XRD, AAS, and Pourbaix diagrams revealed that the poor transition metal recovery originates from the extreme oxidising environment of H2S2O8, which stabilises insoluble high-valent oxides and prevents reductive dissolution pathways. The results highlight that direct application of H2S2O8 is less practical than H2SO4/H2O2 for transition metal extraction but could be exploited for selective Li recovery or integrated into a three-step process: (i) in situ H2SO4/H2O2 generation, (ii) controlled hydrolysis to H2SO4 + H2O2, and (iii) reductive leaching. This approach offers industrial advantages, including on-site oxidant production and the elimination of H2O2 transport hazards. This journal is
Text of the article Перейти на текст статьи
Al-Farabi Kazakh National University, Department of Chemistry and Chemical Technology, Almaty, Kazakhstan
Al-Farabi Kazakh National University
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026