Transition-Metal-Doped M-Li₈ZrO₆ (M = Mn, Fe, Co, Ni, Cu, Ce) as High-Specific-Capacity Li-Ion Battery Cathode Materials: Synthesis, Electrochemistry, and Quantum Mechanical Characterization

Abstract

Lithium-ion batteries (LIBs) are promising devices for high capacity, rechargeable electrical energy storage; however, LIBs are currently limited by the low specific capacity of the cathode compared to the anode. In previous work, our group demonstrated the viability of a novel cathode material, Li8ZrO6 (LZO), through computational and experimental results. Here we report a general synthesis for transition-metal-doped LZO, and we study the effects of doping on electrochemical delithiation and relithiation. A synthesis using transition-metal (M) doped ZrO2 nanoparticle/carbon black composites as precursors produces doped M-LZO with grain sizes between 35 and 67 nm. The materials were tested as electrode materials. Specific capacities of the doped materials depend on the transition metal and on the Li:Zr ratio used in the synthesis, but they are generally higher than in similarly prepared undoped LZO. In this set of cathode materials, Fe3+-doped LZO/C composites showed the highest specific capacities, with an initial discharge capacity higher than two Li ions per formula unit, a specific capacity of 175 mAh/g maintained after 140 cycles, and a specific capacity greater than 80 mAh/g at a rate of 5C. The effects of doping were also investigated by density functional calculations of dopant locations, band gaps, and delithiation energies. We found that all of the dopants that we studied are more favorably located in Li ion sites than in Zr ion sites. The calculated doping effects on structural parameters agree well with experiments. We also found that doping with any of these ions leads to smaller band gaps. Electronic structure calculations with the HSE06 exchange-correlation functional show that deintercalation after doping with Ce3+, Cu2+, or Co2+ at a Li site decreases the attainable cell voltage, whereas Fe3+ doping at a Li site increases it. Because of the large polarization and high carbon content of the M-LZO/C composite electrodes, further materials optimization will be needed before they become practical for LIBs.

Studies on solid state reactions of atomic layer deposited thin films of lithium carbonate with hafnia and zirconia

“…13 Doped Li8ZrO6, on the other hand, has been suggested as a possible cathode material for Li-ion batteries. 15,16…”

A Cobalt‐Free Li(Li0.17Ni0.17Fe0.17Mn0.49)O2 Cathode with More Oxygen‐Involving Charge Compensation for Lithium‐Ion Batteries

“…[14] LNCMO and LNFMO have a similar redox processes. We applied the simplified approach to the GGA + U method introduced by Dudarev et al, [47] in which the parameters U and J do not enter separately,a nd only the difference (UÀJ)i sm eaningful;h ence, we will simply call the parameter U, similar to the work of Huang et al [48,49] The redox process of the Co-containing Li-rich Li ( The oxidation states of Ni, Fe (Co), Mn, and Oi nt he LNFMO (LNCMO) system are + 2, + 3(+ 3), + 4, and À2, respectively.T he electron configuration of Fe 3 + is d 5 .E ach Fe 3 + ion has five spin-up electrons in the high-spin (HS) states, and there are three spin-up electrons and two spin-down electrons for each Fe 3 + ion in the low-spin (LS) states. In this case, peroxo-like OÀO bonds are not formed and Fe substitution avoidst he concentrated accumulationo fo xygen oxidation and thusr ealizes a balanceb etween high capacity and high stability.This provides new scope in designing cobalt-free, low-cost, and higherenergy-density cathode materials for Li-ion batteries.…”

“…Figure 1a). We applied the simplified approach to the GGA + U method introduced by Dudarev et al, [47] in which the parameters U and J do not enter separately,a nd only the difference (UÀJ)i sm eaningful;h ence, we will simply call the parameter U, similar to the work of Huang et al [48,49] The redox process of the Co-containing Li-rich Li (Li 0.17 [50] for all the LS and HS states, coupling between the Fe 3 + ions may be ferromagnetic (FM) or antiferromagnetic (AFM). The calculated results show that the energy of Li 28Àx Ni 4 Fe 4 Mn 12 O 48 in the FM state is higher than that in the AFM state, except for x = 0, 14, and 24.…”

Understanding the Role of Surface Oxygen in Hg Removal on Un‐Doped and Mn/Fe‐Doped CeO2(111)

“…In the whole calculation process, we considered the spin polarization effect on the system, spin polarized calculation was performed and the parameter of ISPIN was selected as 2 in the INCAR file. For the DFT + U calculations, U Hubbard values of 5.0 eV for Ce, 4.5 eV for Mn, and 4.3 eV for Fe were applied.…”