A review of nickel-rich layered oxide cathodes: synthetic strategies, structural characteristics, failure mechanism, improvement approaches and prospects

High Nickel and No Cobalt─The Pursuit of Next-Generation Layered Oxide Cathodes

“…Eliminating Co and increasing Ni in layered NCM cathodes conforms to the future demands of LIBs and has become the preferred development strategy of battery manufacturers . LiNiO 2 (LNO) has thus re-emerged in the public consciousness as a promising starting material for Co-free cathodes, despite the fact that it was long overlooked because of numerous inherent issues such as off-stoichiometry, Li/Ni exchange, Ni 3+ instability, poor thermal stability, low Coulombic efficiency, multiple phase transitions, and fast capacity fading upon cycling. , Foreign heteroatom doping, such as Co, Mg, Al, Mn, and others, has generally been considered a good option for stabilizing the layered structure and enhancing the electrochemical reversibility to alleviate these issues of LNO. − In addition, Co as the most successful substitution can be incorporated into LNO at high enough levels.…”

Effect of Synthesis Processes on the Microstructure and Electrochemical Properties of LiMnPO4 Cathode Material

“…LiMnPO 4 with a high band gap (3.8 eV) demonstrates insulator characteristics . Differing from the three-dimensional tunnels of spinel LiMn 2 O 4 and two-dimensional tunnels of LiNi x Co y Mn 1‑ x ‑ y O 2 (0 ≤ x , y ≤ 1), Li + ions migrate along a one-dimensional tunnel ( b -axis direction) in LiMnPO 4 . , The energy barrier of Li + ion diffusion is high, and the movement speed of Li + ions is limited in the LiMnPO 4 structure. Furthermore, Mn 2+ is oxidized to Mn 3+ during Li + ions extraction.…”

Scalable Advanced Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials from a Slug Flow Continuous Process

“…However, during the continuous charge–discharge cycling, the transformation of Ni 4+ into the lower valent nickel oxides causes an abrupt phase change from layered to rocksalt structure. , The change in crystal structure facilitates the consumption of exposed active Li + by electrolyte leading to the formation of cathode electrolyte interface (CEI), resulting in the reduction of discharge capacity of the active material . Besides this, the corrosion of cathode material by HF, cation mixing, and the formation of an inert layer of Li 2 CO 3 /LiOH on the surface of active material are a few of the standing issues with the layered NCM811, which are required to be addressed. − Various modification techniques, including coating, doping, morphology design, and regulating the crystal structure, are already reported in the literature to overcome the aforementioned limitations. − …”

“… 18 − 22 Various modification techniques, including coating, doping, morphology design, and regulating the crystal structure, are already reported in the literature to overcome the aforementioned limitations. 23 − 25 …”