The successful implementation of an aqueous-based electrode manufacturing process for nickel-rich cathode active materials is challenging due to their high water sensitivity. In this work, the surface of LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) was modified with a lithium phosphate coating to investigate its ability to protect the active material during electrode production. The results illustrate that the coating amount is crucial and a compromise has to be made between protection during electrode processing and sufficient electronic conductivity through the particle surface. Cells with water-based electrodes containing NCA with an optimized amount of lithium phosphate had a slightly lower specific discharge capacity than cells with conventional Nmethyl-2-pyrrolidone-based electrodes. Nonetheless, the cells with optimized water-based electrodes could compete in terms of cycle life. the active material by applying surface coatings seems to be very promising. [6-11,16] LiNiCoAlO 2 (NCA) has attracted significant attention as a cathode active material because of its high energy density. [17] However, NCA is known to be extremely sensitive to moisture, [15,18-20] making it a difficult candidate for the aqueous electrode processing. According to the results in the literature, it is assumed that aqueous processing of NCA will not be successful without additional surface modifications, prior to electrode fabrication [10,11] or in situ surface modification during processing [8,9] or in a combination of both. [21] The strong PÀ O-bonding energy in the PO 4 3À ion gives metal phosphates high structural stability against chemical attack. [22-24] Various phosphate coatings such as Ni 3 (PO 4) 2 , [25] FePO 4 , [26] LiMnPO 4 , [27] MgHPO 4 , [28] BiPO 4 , [29] Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 , [30] Li 3 PO 4 , [23,31] Co 3 (PO 4) 2 , [32,33] LiFePO 4 , [34] and AlPO 4 [31,33,35] have been studied on NCA and resulted in improved electrochemical performance. However, to the best of the authors' knowledge, a phosphatecoated NCA has never been used in a combination with a waterbased electrode manufacturing process. Amongst the phosphate coatings mentioned above, Li 3 PO 4 is relatively easy to synthesize and, in contrast to other metal phosphates such as Ni 3 (PO 4) 2 , Co 3 (PO 4) 2 , BiPO 4 , FePO 4 , MgHPO 4 , and AlPO 4, a lithium-ion conductor. [36,37] The latter aspect might comparatively facilitate the migration of lithium ions through the particles surface. Therefore, in this study, the surface of LiNi 0.8 Co 0.15 Al 0.05 O 2 particles was modified by applying Li 3 PO 4 coatings via a simple precipitation reaction. The modified particles are compared with pristine NCA in terms of their processability in water and their electrochemical performance in cells. Finally, the cycle stability of cells with electrodes prepared via an aqueous and the conventional NMP route as reference is investigated.

A lithium phosphate surface coating can protect water-sensitive LiNi0.8Co0.15Al0.05O2 (NCA) particles during aqueous electrode manufacturing. Herein, the coating process was performed by using a spray drying process, an easy method for upscaling. The coating provides enhanced protection against water that is reflected in a significantly reduced formation of detrimental water-induced surface species. As a consequence, full cells containing water-based electrodes with coated NCA and graphite anodes demonstrate good long-term 1C cycling performance with a capacity retention of 80% maintained after more than 730 cycles and a remaining capacity of approximately 130 mAh g−1.

To reduce the ecological footprint and to increase the lifetime of lithium‐ion batteries (LIBs), it is necessary to understand aging phenomena inside the cells during cycling. In this study, the positive effect of external pressure through bracing the cells on aging is investigated for automotive battery cells with more than 7000 cycles. After cycling, the aged cells are studied by using post‐mortem analysis. It is shown that bracing does not affect the anode and cathode in the same manner. A lack of external pressure results in lithium plating due to contact losses on the anode. Such a loss of lithium inventory plays only a small role in the braced cells. However, the structural and morphological degradation, such as particle cracking at the cathode, is significant. Half‐cell tests of aged and unaged anode samples extracted from the automotive cells confirm the post‐mortem findings, where only minimal differences can be seen for the braced cell. In contrast, the aged cathodes from braced cells demonstrate substantial capacity fade in half‐cell measurements as compared to the cathodes extracted from the unbraced cell. Finally, a new concept of the mechanical state of health (mechanical SOH) is introduced to correlate mechanical effects with electrode degradation.

Li‐Ion Batteries In article number 2102448, Guinevere A. Giffin, and co‐workers demonstrate the new concept of mechanical state‐of‐health to describe the positive effect of external bracing on the performance of automotive lithium‐ion cells. This new concept correlates electrode degradation with mechanical effects and shows that external bracing does not affect anode and cathode aging in the same way.

Ternary composite bulk cathodes consisting of particulate active material (AM), solid-state electrolyte (SSE) and electrical conductor are essential to achieve competitive ceramic all solid-sate batteries (ASSBs). Firmly bonded contacts between...