Grain boundary driven capacity fade/hysteresis abated in composite cathode material for lithium-ion batteries/pouch cell

• Charge transport (Li+, e−) across edges of faceted particles costs much energy.
• Smooth surfaced, fade abated composite cathode particles.
• Electrochemical hysteresis (irreversibility) predicted through CV.
• Li vs LNMC-LNM cell delivered discharge capacity of 194 mAh g−1 (ΔQLi = −11%).
• W-weaving style Li-ion pouch cell fabricated with composite cathode/anode.

The composite cathode material LiNi1/3Mn1/3Co1/3O2:LiNi0.5Mn0.5O2 (wt. % 75:25) comprising the blend of well characterized LiNi1/3Mn1/3Co1/3O2 and LiNi0.5Mn0.5O2 materials has been synthesized through a facile thermolysis employing mixed hydroxy-carbonate precursor. This composite cathode material yielded impressive charge–discharge profile with a capacity of 213/194 mAh g−1 at 0.1 C and amazing coulombic efficiency of 99.4% at 50th cycle. Notwithstanding impressive initial charge–discharge capacity of the individual LNMC phase 224/187 mAh g−1 attributed to sharp edges of the cathode particles showed large irreversible capacity-hysteresis. Near absence of irreversible capacity observed upon discharging the composite cathode material can be attributed to milled/smoothened cathode particles of the composite cathode material offering little scope for energy loss in contrast to sharp edge-grain boundary induced irreversibility-hysteresis seen in the individual phases (LiNi1/3Mn1/3Co1/3O2 and LiNi0.5Mn0.5O2). The application scope of the high performance composite cathode material has been widened in conjunction with graphitic alloy anode (G0.65Ni0.05Ti0.15Sn0.15) material as demonstrated with the fabrication of W-weaving style design of Li-ion pouch cell (∼500 mAh) at moderate loads 0.12 Wh, 1.1 Wh.

Comparison of charge densities and energetic consideration for transportation of charges (Li+, e−) across the edges of faceted particles of individual cathodic phase(s) vs moving over smooth particle surface of the composite cathode material for explaining low irreversibility-abated hysteresis of the composite phase.Figure optionsDownload as PowerPoint slide