Comment on “Zinc/selenium conversion battery: a system highly compatible with both organic and aqueous electrolytes” by Z. Chen, F. Mo, T. Wang, Q. Yang, Z. Huang, D. Wang, G. Liang, A. Chen, Q. Li, Y. Guo, X. Li, J. Fan and C. Zhi, Energy Environ. Sci., 2021, 14, 2441

The discharge capacity between 0.7 and 1.5 V is due to the conversion of Se 4+ to Se(0).