Many publications have demonstrated the beneficial effects of Mn and Na ions as additives in ZnSO4 electrolyte on zinc
manganese batteries (ZMB) performance with low cathode loadings (<5mgcm−2). For commercial applications, however, higher
loadings are needed. This work investigates the effects of MnSO4 and Na2SO4 concentration in 1M ZnSO4 on the ZMB perfor
mance with a high δ-MnO2 cathode loading of 10 mg cm−2. After the addition of 0.3M MnSO4 and 1M Na2SO4 into base elec
trolyte, ZMB capacity increased from 96 to 178mAhg−1. In XRD spectra, no major phase change was observed besides the
emergence of a layered Mn7O13·5H2O phase that grew with increasing cycle number. XPS analysis of MnO2 cathode after partial
discharge step of ZMB until 1.3 V revealed predominance ofMn(III) species compared toMn(IV), confirmingits reduced state due
to intercalated Zn2+ ions. The addition of Na2SO4 improved electrolyte conductivity, allowing for 100 charge/discharge cycles
(1000 h) at C/5. Capacity fading was assigned to zinc corrosion and irreversible zinc sulfate hydroxide (ZSH) within the cathode.
After chemical ZSH removal step, ZMB with reused MnO2 cathode delivered 151mAhg−1 in ZM0.3NS, confirming positive effect
of both additives on MnO2 structure stability
