π-type orbital hybridization and reactive oxygen quenching induced by Se-doping for Li-rich Mn-based oxide cathode

Transition Metal Vacancy in Layered Cathode Materials for Sodium‐Ion Batteries

“…Wang's group observed the ordered native vacancy in Na 4/ 7 Mn 6/7 & 1/7 O 2 along [001] zoom axis both in HAADF and ABF images. [54] in the HAADF field along the [100] direction, due to the relative weak projection of contrast, [38,40] as seen in Figure 5a. [28] Copyright 2019, American Chemical Society, P2-Na 0.76 Ca 0.05 [Ni 0.23 & 0.08 Mn 0.69 ]O 2 , reproduced with permission.…”

“…From this aspect, surface modifications were taken into consideration. As a well‐known anti‐aging and oxygen‐radicals capturing element, Se was respectively introduced into LiCoO 2 , [98] NMC811 [99] and Li‐rich Mn‐based oxide [100] to catch the escaped oxygen to prevent it from attacking the electrolyte. Meanwhile, Se with weak electronegativity rearranged the electrons around lattice O and manipulate the molecular polarity within the structure, which benefit O 2 p −Mn 3 d hybridization and mitigate the lattice O loss.…”

“…[28] Copyright 2019, American Chemical Society, P2-Na 0.76 Ca 0.05 [Ni 0.23 & 0.08 Mn 0.69 ]O 2 , reproduced with permission. [38] Copyright 2021, Wiley-VCH, and P2-Na 0.75 Ca 0.04 [& 0.03 Li 0.1 Ni 0.2 Mn 0.67 ]O 2 along [100] direction at the pristine state. Reproduced with permission.…”

Review on comprehending and enhancing the initial coulombic efficiency of Li-rich Mn-based cathode materials in lithium-ion batteries

“…42,43 Recently, electrochemically stable LMOs were successfully designed by manipulating the molecular polarity within the host structure through the introduction of Se. 44 The Se-LMOs deliver excellent long cycling stability after 400 cycles with only a 0.029% capacity fading and 1.37 mV potential decline per cycle. The co-doping facilitated the Li diffusion but also minimized the O 2p redox reported by Vanaphuti et al.…”

Constructing a surface spinel layer to stabilize the oxygen frame of Li-rich layered oxides

“…To date, multifarious approaches have been investigated to stabilize the O-redox process, such as surface coating, [20][21][22] bulk doping [23][24][25][26][27] and surface chemical treatment, 28,29 so as to improve the structural stability of Li-rich cathodes. For instance, Peng et al 30 regulated the O-redox process by the NiFe 2 O 4 coating, which effectively reduces the oxygen accumulation during the cycle to improve the initial coulombic efficiency and reduce the loss of capacity.…”