In this work, a facile, wet chemical synthesis was utilized to achieve a series of lithium manganese oxide (LiMn₂O₄, (LMO) with 1–5%wt. graphene oxide (GO) composites. The average crystallite sizes estimated by the Rietveld method of LMO/GO nanocomposites were in the range of 18–27 nm. The electrochemical performance was studied using CR2013 coin-type cell batteries prepared from pristine LMO material and LMO modified with 5%wt. GO. Synthesized materials were tested as positive electrodes for Li-ion batteries in the voltage range between 3.0 and 4.3 V at room temperature. The specific discharge capacity after 100 cycles for LMO and LMO/5%wt. GO were 84 and 83 mAh g⁻¹, respectively. The LMO material modified with 5%wt. of graphene oxide flakes retained more than 91% of its initial specific capacity, as compared with the 86% of pristine LMO material.

In this study, the activation energy and ionic conductivity of the Li₆PS₅Cl material for all-solid-state batteries were investigated using solid-state nuclear magnetic resonance (NMR) spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that the activation energy values estimated from nuclear relaxation rates are significantly lower than those obtained from impedance measurements. The total ionic conductivities for long-range lithium diffusion in Li₆PS₅Cl calculated from EIS studies depend on the crystal size and unit cell parameter. The study also presents a new sample preparation method for measuring activation energy using temperature-dependent EIS and compares the results with the solid-state NMR data. The activation energy for a thin-film sample is equivalent to the long-range lithium dynamics estimated from NMR measurements, indicating the presence of additional limiting processes in thick pellets. Additionally, a theoretical model of Li-ion hopping based on results obtained using density-functional theory methods in comparison with experimental findings was discussed. Overall, the study emphasizes the importance of sample preparation methods in determining accurate activation energy and ionic conductivity values for solid-state lithium batteries and the significance of solid-state electrolyte thickness in new solid-state battery design for faster Li-ion diffusion.

In this study, we focus on the large-scale ex situ Raman mapping of LiMn2O4 (LMO) electrodes maintained at varying states of charge. A comprehensive statistical analysis has been conducted at an area of ca. 3660 μm2 on more than 3100 collected spectra for each LMO electrode sample. High-definition ex situ Raman maps provide profound insight into the lithiation process, offering an additional perspective on the mechanism of LMO intercalation. These maps clearly depict the coexistence of two phases, with evident phase transitions and state-of-charge gradients. The set of spectra with various state-of-charge has been successfully deconvoluted taking into account the two-phase character of the ongoing reaction. In addition, we performed the study on the samples operated for 50 cycles at the high C-rates and tracked their delithiation state and impurity formation. This technique serves as a complementary visualization and analytical tool alongside other bulk-type methods employed in battery diagnostics. Importantly, this ex situ Raman mapping approach is applicable to any electrode material exhibiting a Raman response.

Among the many studied Li-ion active materials, silicon presents the highest specific capacity, however it suffers from a great volume change during lithiation. In this work, we present two methods for the chemical modification of silicon nanoparticles. Both methods change the materials’ electrochemical characteristics. The combined XPS and SEM results show that the properties of the generated silicon oxide layer depend on the modification procedure employed. Electrochemical characterization reveals that the formed oxide layers show different susceptibility to electro-reduction during the first lithiation. The single step oxidation procedure resulted in a thin and very stable oxide that acts as an artificial SEI layer during electrode operation. The removal of the native oxide prior to further reactions resulted in a very thick oxide layer formation. The created oxide layers (both thin and thick) greatly suppress the effect of silicon volume changes, which significantly reduces electrode degradation during cycling. Both modification techniques are relatively straightforward and scalable to an industrial level. The proposed modified materials reveal great applicability prospects in next generation Li-ion batteries due to their high specific capacity and remarkable cycling stability.

In recent years, a type of layered oxide, LiNi x Mn y Co z O2 (NMC) where x+y+z = 1, has become the preferred cathode material for electric vehicle (EV) batteries. Despite some disorder in the crystal structure due to Li+/Ni2+ cation mixing, the composition offers a high specific capacity of up to 200 mAh g-1 at 4.3 V vs Li|Li+. The objective of this study is to comprehensively evaluate the structural and electrochemical changes in NMC811 after storage in ambient conditions. In this report, we study stoichiometric and Li-rich NMC811 in terms of their structural, morphological, and electrochemical differences. Following literature reports, a rigorous aqueous washing procedure was used alternatively to remove a possible lithium excess from the NMC surface. The findings of this study hold immense significance as they focus on the potential challenges that may arise due to the remaining lithium content or Li+ extraction from the near-surface NMC811 materials. There is no consensus in the literature on whether excess lithium can harm the material's structural and electrochemical properties, reduce performance and safety concerns, or be beneficial regarding its protective properties, for Ni-rich NMC. Proper treatment of as-synthesized Ni-rich NMCs helps to develop procedures to address the residual lithium compounds issues, leading to enhanced performance and safety. Here with this report, we show another aspect not being considered in the literature before, regarding morphological NMC811 reshaping and a mechanism of LRC transition and growth due to aging. In addition, we linked the selected structural parameters to the electrochemical performance of various NMC811 materials. We discuss the well-known structural factors and their limitations and introduce a doublet resolution criterion that can help in predicting electrochemical performance.