High Energy Density Single Crystal NMC/Li6PS5Cl Cathodes for All-Solid-State Lithium Metal Batteries

Abstract

<div><div><div><p>To match the high capacity of metallic anodes, all-solid-state batteries (ASSBs) re- quire high energy density, long-lasting composite cathodes such as Ni-Mn-Co (NMC)- based lithium oxides mixed with a solid-state electrolyte (SSE). However in practice, cathode capacity typically fades due to NMC cracking and increasing NMC/SSE in- terface debonding because of NMC pulverization, which is only partially mitigated by the application of a high cell pressure during cycling. Using smart processing proto- cols we report a single crystal particulate LiNi0.83Mn0.06Co0.11O2 and Li6PS5Cl SSE composite cathode with outstanding discharge capacity of 210 mAh g−1 at 30 °C. A first cycle coulombic efficiency of >85%, and >99% thereafter, was achieved despite a 5.5% volume change during cycling. A near-practical discharge capacity at a high areal capacity of 8.7 mAh cm−2 was obtained using a novel asymmetric anode/cathode cycling pressure of only 2.5 MPa/0.2 MPa.</p></div></div></div>

Which Exchange Current Densities Can Be Achieved in Composite Cathodes of Bulk-Type All-Solid-State Batteries? A Comparative Case Study

“…Figure 2 shows the first galvanostatic charge/discharge cycle of the LCO-based battery and of the NMC-based battery, respectively. The cathode thickness was 52 and 57 μm, respectively, and the batteries were cycled at a rate of 0.1 C. The observed discharge capacities in the first cycle are in good agreement with practical capacities reported for LCO 38,39 in the range of 180−200 mAh g −1 and for NMC 40,41 in the range of 190−200 mAh g −1 , respectively.…”

Role of Areal Capacity in Determining Short Circuiting of Sulfide-Based Solid-State Batteries

“…Full-Cell Assembly. The composite cathode was prepared following a procedure similar to that reported by Doerrer et al 43 A 1.4 g mixture of 70 wt % LiNbO 3 -coated LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811, NEI Corp.), 27.5 wt % LPSC, and 2.5 wt % Super P carbon black (MTI) was added to a ZrO 2 jar with 18 ZrO 2 balls (10 mm diameter) inside an argon-filled glovebox. The jar was then sealed and removed from the glovebox for milling in a planetary ball mill (Fritsch Pulverisette 7).…”

Solid-state lithium battery cathodes operating at low pressures

“…High pressures used in many studies of SSBs mask or overcome this effect by pressing the particles back into contact; the capacity fade of SSBs is much more significant at low pressures. 34 However, by using 4.2 V instead of a 4.4 V cutoff, the volume change of the CAM is reduced from approximately 6% to 2.5%, and a capacity retention of 94% rather than 65% was obtained after 50 cycles for a reduction in capacity of only 14%. This work highlights the imperative of finding highly conducting SEs to reduce the amount of SE in the composite cathode, thereby increasing the CAM loading to deliver high capacities at high rates, low stack pressures, and ambient temperatures.…”

“…The absence of CAM cracking is confirmed by the cross-sectional SEM image of the composite cathode in Figure S4. 34 A layer of Li 3 InCl 6 is located adjacent to the cathode, and a further layer of Li 6 PS 5 Cl is placed between this and the Li-In alloy acting as the second electrode. Li 3 InCl 6 is unstable when in contact with the reducing anode, and the inclusion of Li 6 PS 5 Cl avoids this problem.…”