The role of niobium in layered oxide cathodes for conventional lithium-ion and solid-state batteries

Abstract

This review article highlights the advantages of niobium as a dopant and a coating constituent for improving cycling performance of layered Ni-rich oxide cathodes in liquid- and solid-electrolyte-based Li-ion batteries.

Interface and Electrode Microstructure Engineering for Optimizing Performance of the LiNiO2 Cathode in All-Solid-State Batteries

“…Overall, the DEMS results indicate that the coating is somewhat capable of mitigating the release of lattice oxygen or, in other words, inhibiting the surface phase transformation from layered to spinel/rocksalt and loss of electrochemically active material . This is likely related, to some degree, to the interdiffusion of Nb 5+ into the LiNiO 2 , as confirmed by high-resolution STEM (see Figure S5), which apparently (indirectly) helps to reduce the surface oxygen activity. ,,, …”

“…44 This is likely related, to some degree, to the interdiffusion of Nb 5+ into the LiNiO 2 , as confirmed by high-resolution STEM (see Figure S5), which apparently (indirectly) helps to reduce the surface oxygen activity. 19,21,28,45 The data presented above provide profound evidence for the positive effect of the coating in stabilizing the cathode interface (see Figure 5), which is beneficial to the cell cyclability and explains why the coated CAM exhibits better performance, despite the larger absolute changes in unit-cell volume during battery operation.…”

“…25,26 Aside from that, highresolution STEM imaging suggests some tendency toward niobium surface doping and further revealed the presence of rocksalt-like regions in the vicinity of the LiNiO 2 |coating interface (see Figure S5). 27,28 As can be seen from the STEM image shown in Figure S6, the 0.36 wt % coated CAM exhibits an (isolated) island-type coating structure (relatively low surface coverage), whereas the 0.76 and 1.38 wt % coated samples share similar properties with regards to coating thickness and uniformity (see Figures 2a and S7). This apparent difference is also reflected in the electrochemical response.…”

Protective Nanosheet Coatings for Thiophosphate‐Based All‐Solid‐State Batteries

“…As mentioned previously, residual lithium is probably being consumed to some degree by the nanosheets during post-processing in the formation of Li x NbO y , which itself is a well-established coating material in LIBs and SSBs. [45] For that reason, this kind of coating will be investigated in more detail in the future.…”

“…The latter materials are known as functional coatings and can be readily obtained in nanosheet format. [41][42][43][44][45] WS 2 is found to undergo side reactions with the NCM particles upon mild annealing, and electrochemical testing shows that nanosheet coating leads to stability improvements in SSBs, but not in LIB cells. This highlights the differences in stabilization strategies for batteries with liquid and solid electrolytes and emphasizes the need for further studies.…”