Free Energy for Protonation Reaction in Lithium-Ion Battery Cathode Materials

Abstract

Calculations are performed of free energies for proton-for-lithium-ion exchange reactions in lithiumion battery cathode materials. First-principles calculations are employed for the solid phases and tabulated ionization potential and hydration energy data for aqueous ions. Layered structures, spinel LiMn 2 O 4 , and olivine LiFePO 4 are considered. Protonation is most favorable energetically in layered systems, such as Li 2 MnO 3 and LiCoO 2 . Less favorable are ion-exchange in spinel LiMn 2 O 4 and LiV 3 O 8 . Unfavorable is the substitution of protons for Li in olivine LiFePO 4 , because of the large distortion of the Fe and P coordination polyhedra. The reaction free energy scales roughly linearly with the volume change in the reaction.

New class of nonaqueous electrolytes for long-life and safe lithium-ion batteries

“…When LiPF 6 was replaced by Li 2 B 12 F 12 , the onset temperatures for these two reactions increased to 215°C and 270°C, respectively (Fig. 8c,d), due to the lack of HF in the electrolyte, which is believed to promote the thermal decomposition of delithiated cathodes 21 . Similar observation was also obtained for the sample using Li 2 B 12 F 9 H 3 -based electrolyte, the onset temperature for the interested reactions was 214°C and 256°C, respectively (Fig.…”

Progress in Rechargeable Aqueous Zinc‐ and Aluminum‐Ion Battery Electrodes: Challenges and Outlook

“…Three strategies can be adopted to reduce proton/hydronium coinsertion: 1) increasing the electrolyte pH, 2) using supersaturated salt solutions, 3) choosing appropriate crystal structures for the host, as the protonation has been shown to be dependent on the host crystal structure . Crystal structures showing higher lattice distortion during proton insertion will be least accommodating to H + .…”

Perspectives in Lithium Batteries

“…Based on DFT calculations, Benedek et al 117 concluded that proton intercalation in layer compounds is much more favorable than for the spinel LiMn 2 O 4 and impossible in LiFePO 4 . Based on DFT calculations, Benedek et al 117 concluded that proton intercalation in layer compounds is much more favorable than for the spinel LiMn 2 O 4 and impossible in LiFePO 4 .…”