Layered P2-Na2/3Co1/2Ti1/2O2 as a high-performance cathode material for sodium-ion batteries

Evidence of a Pseudo‐Capacitive Behavior Combined with an Insertion/Extraction Reaction Upon Cycling of the Positive Electrode Material P2‐NaxCo0.9Ti0.1O2 for Sodium‐ion Batteries

“…The sample reveals agglomerated particles with sizes in the micrometer range and hexagonal shape. The presence of rough features is attributed to sodium carbonates as already revealed by our previous work on P2‐Na 0.66 Co 1‐y Ti y O 2 (y=0.05 and 0.5)…”

“…Another study on Na 2/3 Mn 2/3 O 2 demonstrated a discharge capacity of 98 mAh/g at 1 C in the potential range of 1.5–3.75 V versus Na + /Na . Even for Na 0.66 Co 0.95 Ti 0.05 O 2 and Na 0.66 Co 0.5 Ti 0.5 O 2 recently studied by our group, the discharge capacity at 5 C were around 70 and 30 mAh/g, respectively.…”

“…Herein, we continue to report the cobalt titanium combination which constitutes an unexplored opportunity in SIBs cathode materials. Based on the effect of titanium on the structure stability and extending the cycle life of the battery as well as reversible capacity and encouraged by our previous work, we wish to continue our investigations on the effect of titanium substitution on NaCoO 2 and we will focus onto Na x Co 0.9 Ti 0.1 O 2 . The electrode material was synthesized using solid state method, and was subjected to different electrochemical tests, mainly within the potential range 2–4.2 V. Galvanostatic cycling with potential limitations, has shown an initial charge capacity of 108 mAh/g, a weak polarization as well as reversible electrochemical processes, which are also confirmed by cyclic voltammetry.…”

Sodium‐Ion Batteries: Building Effective Layered Cathode Materials with Long‐Term Cycling by Modifying the Surface via Sodium Phosphate

“…Many reports have dealt with P2‐type Na 2/3 MeO 2 ; i.e., Na 2/3 MnO 2 , Na 2/3 CoO 2 , Na 2/3 VO 2 , Na 2/3 [Ni 1/3 Mn 2/3 ]O 2 , Na 2/3 [Fe 1/2 Mn 1/2 ]O 2 , Na 2/3 [Co 2/3 Mn 1/3 ]O 2 , Na 2/3 [Co 1/2 Ti 1/2 ]O 2 , and Na 0.67 [Mn 0.65 Ni 0.2 Co 0.15 ]O 2 . Earlier work by Yabuuchi et al demonstrated that P2 Na 2/3 Fe 1/2 Mn 1/2 O 2 can deliver a capacity of ≈190 mAh g −1 based on the Me 3+ /Me 4+ (Me: Fe 1/2 Mn 1/2 ) redox couples, which represents 72% of the theoretical capacity in the average voltage range of 1.5–4.3 V. Further, recent work by Yuan et al showed that P2 Na 0.67 [Mn 0.65 Fe 0.20 Ni 0.15 ]O 2 could deliver a high capacity of ≈210 mAh g −1 in the average voltage range of 1.5–4.3 V. However, some P2‐type materials, representatively Na 2/3 [Ni 1/3 Mn 2/3 ]O 2 and derivatives activated by the Ni 2+/4+ redox couple, undergo serious capacity fading during extended cycling due to phase transformation from the P2 to O2 phase.…”

V2O5·nH2O nanosheets and multi-walled carbon nanotube composite as a negative electrode for sodium-ion batteries

“…Sodium-ion batteries (SIBs) are vastly investigated as a viable alternative to lithium-ion battery (LIBs), as they have potential to provide a similar energy density to that in LIBs, while sodium is more naturally abundant than lithium [1,2] . Therefore, different anode and cathode materials have been tested in SIBs in last couple of years [3][4][5][6] . Hard carbon has been suggested as an interesting negative electrode (anode) material for SIBs due to its high specific capacity and cycling stability [2] .…”