Effect of Amorphous LiPON Coating on Electrochemical Performance of LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) in All Solid-State Batteries

Abstract

High nickel layered oxide LiNi0.8Mn0.1Co0.1O2 (NMC811) was coated with a nanometer layer coating of a lithium ion conducting solid electrolyte, lithium phosphorus oxynitride (LiPON) by using RF-magnetron sputtering. The cells with LiPON coated NMC811 exhibit much improved cycling performance compared to the cells with pristine NMC811 with 64.1% and 42.6% capacity retention respectively over 100 cycles in an all solid-state battery. The LiPON layer provides interfacial stability at high voltages, suppresses the growth of impedance with cycling and improves the rate capability. Thicker coatings show a negative impact on the performance owing to the increase in electronic resistance with increasing thickness of the LiPON layer. The dQ/dV analysis, electrochemical impedance spectroscopy (EIS), and the overpotential study during galvanostatic cycling were conducted to elucidate the improvement of the cycling stability and enhancement of Li+ transport through LiPON layers surrounding NMC811.

Insights into interfacial chemistry of Ni-rich cathodes and sulphide-based electrolytes in all-solid-state lithium batteries

“…A series of coating materials have been constructed for Ni-rich cathodes, including Li + -conducting coating layers ( e.g. LiNbO 3 , 114,155–158 Li 2 ZrO 3 , 119,159,160 Li 4 Ti 5 O 12 , 161–163 LiAlO 2 , 118,164 Li 2 MoO 4 , 165 Li 3 PO 4 , 166 LiTaO 3 , 129 Li 3 B 11 O 18 , 109 LiPON, 167 LiNb 0.5 Ta 0.5 O 3 , 131,168,169 Li 0.35 La 0.55 TiO 3 , 125 Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , 170 Li 0.35 La 0.5 Sr 0.05 TiO 3 , 171 Li 2 CO 3 –LiNbO 3 , 115 Li 2 CO 3 –Li 2 ZrO 3 172 and LiInO 2 –LiI 173 ), binary oxides ( e.g. Al 2 O 3 , 164 ZrO 2 , 174 HfO 2 175 and TiO 2 176 ) and carbon-based materials.…”

Enhancing Moisture and Electrochemical Stability of the Li5.5PS4.5Cl1.5 Electrolyte by Oxygen Doping

“…The overlaps of peaks at 4.2 V from the first to 80 th cycles for both batteries indicate good reversibility of NCM811 from H2 transiting to H3 phase during cycling. While for the Li 5.5 PS 4.425 O 0.075 Cl 1.5 -based solid-state batteries, smaller potential variations (36.0 mV vs 37.9 mV) are observed after 80 cycles, indicating the enhanced reversibility of the cathode using the Odoped electrolyte 42.…”

“…In addition, dQ/dV analysis of those SSBs during cycling is performed to unravel the phase evaluation of the LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode during working. As displayed in Figure5e,f, the oxidation peaks located at 3.73, 3.99, and 4.18 V are related to the phase transition of the NCM811 cathode during charging from H1 to M phases (hexagonal to monoclinic), M to H2 phases (monoclinic to hexagonal), and H2 to H3 phases (hexagonal to hexagonal phases), respectively 42,43. The overlaps of peaks at 4.2 V from the first to 80 th cycles for both batteries indicate good reversibility of NCM811 from H2 transiting to H3 phase during cycling.…”

Unlocking Stable Multi‐Electron Cycling in NMC811 Thin‐Films between 1.5 – 4.7 V

“…Lithium-phosphorus-oxynitride (LiPON) is chosen as a well-established solid-state electrolyte and because of its compatibility with high voltage NMC811 cathodes and lithium metal. [26] A 10-nm LiPON coating was previously used with Li-rich Mn-based Li 1.2 Mn 0.525 Ni 0.175 Co 0.1 O 2 by by Martha et al [27] to improve the capacity retention to ≈250 mAh g -1 after 300 cycles at C/10. In addition, LiPON can compensate for cathode volume changes due to its amorphous nature, which is important in conjunction with Li-rich cathode materials.…”