High areal capacity, long cycle life 4 V ceramic all-solid-state Li-ion batteries enabled by chloride solid electrolytes

Charge–discharge capacity and coulombic efficiency vs cycle number for high voltage LiNi0.85Co0.1Mn0.05O2 all-solid-state batteries (ASSB). The high voltage stability of the solid electrolyte chlorospinel Li2In1/3Sc1/3Cl4 in the cathode composite renders no cathode coating necessary. That leads to fast Li ion and electron percolation within the cathode composite and minimal ion or electron blocking interphase formation during cycling, even up to 4.8 V vs Li+/Li. In the 2.8 – 4.3 V window, high areal capacities up to 4.0 mAh∙cm-2were achieved, and 90% capacity retention over 700 cycles with conventional cathode loading.

Scientific Achievement

Long-lasting, high-loading and high-voltage ASSBs with bare

LiNi1-x-yCoxMnyO2/LiCoO2 and a new chloro-spinel solid electrolyte Li2In1/3Sc1/3Cl4 are demonstrated. The ultra-low electronic conductivity of Li2In1/3Sc1/3Cl4 drives a very wide “kinetic” electrochemical stability window (up to 4.8 V vs Li+/Li) that lies well above its thermodynamic stability limit (4.3 V vs Li+/Li).

Significance and Impact

These ultra-stable, high-voltage and high-loading solid state cells provide valuable insight into the design and development of ASSBs and may serve as an important point of reference. They also provide new insights into the design of new solid electrolytes with emphasis on ultralow electronic conductivity and excellent chemical compatibility between cathode and solid electrolyte.

Research Details

  • A new chloride solid electrolyte Li2In1/3Sc1/3Cl4 was synthesized with a disordered Li-ion sublattice and electronic structure that gives rise to a remarkably high si/se conductivity ratio.
  • Excellent electrochemical performance for bulk ASSBs is demonstrated both for high cathode loading, and high voltage (4.8 V) cathode-active materials (CAMs).
  • Electrochemical impedance spectroscopy and ToF-SIMs show a stable interface is formed between NCM85 and the SE, owing to the high oxidation stability and chemical compatibility of Li2In1/3Sc1/3Cl4 in contact with uncoated oxide CAMs.

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DOI: doi.org/10.1038/s41560-021-00952-0

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