Improved titanium-manganese flow battery with high capacity and high stability

Manganese-based flow battery is desirable for electrochemical energy storage owing to its low cost, high safety, and high energy density . However, long-term stability is a major challenge for its application due to the generation of uncontrolled MnO 2 . To improve the cycle life, we propose a charge-induced MnO 2 -based slurry flow battery (CMSFB) for the first time, where nano-sized MnO 2 is used as redox-active material. The reaction mechanism of MnO 2 is discussed in detail. Benefiting from the electrostatic interaction , MnO 2 particles are homogeneously dispersed in the electrolyte during the charge process and contact sufficiently with the reaction sites of the electrode during the discharge process. As a result, the novel CMSFB exhibits coulombic efficiency of over 99% and energy efficiency of over 85% at a current density of 40 mA cm −2 and can run stably over 1000 cycles without capacity decay. This work opens new opportunities for the development of manganese-based flow batteries and slurry flow batteries.