Practical Realization of O3-Type NaNi _0.5 Mn _0.3 Co _0.2 O ₂ Cathodes for Sodium-Ion Batteries

In this work, we report the practical realization of 3.6 V Sodium-ion coin and multi-electrode pouch-type cells using O3-type layered NaNi _0.5 Mn _0.3 Co _0.2 O ₂ cathodes and dextrose derived hard carbon anodes in one-unit cell. The manuscript provides a thorough study of NaNi _0.5 Mn _0.3 Co _0.2 O ₂ cathodes along with hard carbon anodes and its practical difficulty in the development of Sodium-ion cells. NaNi _0.5 Mn _0.3 Co _0.2 O ₂ cathodes deliver an initial discharge capacity of ∼136 mAhg ⁻¹ with a moderate capacity retention of 87 mAhg ⁻¹ at 0.1C rate after 200 cycles. Similarly, the hard carbon anodes show a reversible capacity of about 280 mAhg ⁻¹ at C/10 rate. The diffusion coefficient of Sodium-ion calculated is in the order of 10 ⁻¹¹ –10 ⁻¹² cm ² s ⁻¹ suggesting good reversibility, capacity retention and C-rate performance of the cathode. Further, no change in peak voltage in dQ/dV plots, XRD patterns, and CVs dictates the crystalline phase stability of NaNi _0.5 Mn _0.3 Co _0.2 O ₂ during cycling. NaNi _0.5 Mn _0.3 Co _0.2 O ₂ retains good structural stability during long cycling and decreased interlayer transition metal ion migration. Engineering aspects for assembling and testing O3-Type NaNi _0.5 Mn _0.3 Co _0.2 O ₂ -hard carbon in the full cell is also investigated thoroughly. Herein, we have taken the research output and challenges from the coin-type cell and applied further to develop single and multi-electrode pouch type-cell of various configurations.