New electrode architectures promise huge potential for improving batteries' electrochemical properties, such as power density, energy density, and lifetime. In this work, the use of laser-induced forward transfer (LIFT) was employed and evaluated as a tool for the development of advanced electrode architectures. For this purpose, it was first confirmed that the printing process has no effect on the transferred battery material by comparing the electrochemical performance of the printed anodes with state-of-the-art coated ones. For this, polyvinylidene fluoride (PVDF) was used as a binder and n-methyl-2-pyrrolidone (NMP) as a solvent, which is reported to be printable. Subsequently, multilayer electrodes with flake-like and spherical graphite particles were printed to test if a combination of their electrochemical related properties can be realized with measured specific capacities ranging from 321 mAh·g-1 to 351 mAh·g-1. Further, a multilayer anode design with a silicon-rich intermediate layer was printed and electrochemically characterized. The initial specific capacity was found to be 745 mAh·g-1. The presented results show that the LIFT technology offers the possibility to generate alternative electrode designs, promoting research in the optimization of 3D battery systems.
Short-range ordering in cation-disordered cathodes can have a significant effect on their electrochemical properties. Here, we characterise the cation short-range order in the antiperovskite cathode material Li2FeSO, using density functional theory, Monte Carlo simulations, and synchrotron X-ray pair-distribution-function data. We predict partial short-range cation-ordering, characterised by favourable OLi4Fe2 oxygen coordination with a preference for polar cis-OLi4Fe2 over non-polar trans-OLi4Fe2 configurations. This preference for polar cation configurations produces long-range disorder, in agreement with experimental data. The predicted short-range-order preference contrasts with that for a simple point-charge model, which instead predicts preferential trans-OLi4Fe2 oxygen coordination and corresponding long-range crystallographic order. The absence of long-range order in Li2FeSO can therefore be attributed to the relative stability of cis-OLi4Fe2 and other non-OLi4Fe2 oxygen-coordination motifs. We show that this effect is associated with the polarisation of oxide and sulfide anions in polar coordination environments, which stabilises these polar short-range cation orderings. We propose that similar anion-polarisation-directed short-range-ordering may be present in other heterocationic materials that contain cations with different formal charges. Our analysis illustrates the limitations of using simple point-charge models to predict the structure of cation-disordered materials, where other factors, such as anion polarisation, may play a critical role in directing both short- and long-range structural correlations.
A new modification of Mn(OH)Cl was obtained under high-pressure/high-temperature conditions in a Walker-type multianvil device. The pale pink, hygroscopic compound crystallizes in the orthorhombic space group Pnma (no. 62) with a = 602.90(4), b = 350.98(2), c = 1077.69(7) pm, and V = 228 × 106 pm3. The layered centrosymmetric structure consists of edge-sharing Mn(OH)3Cl3 octahedra arranged in sheets parallel to the (001) plane. The comparatively long H···Cl distance of 275 pm suggests only weak hydrogen bonds between neighboring layers. Spin-polarized scalar-relativistic DFT+U calculations predict a non-conducting magnetically ordered ground state with a band gap of at least 3.2 eV and an effective magnetic moment of 4.65 µB/f. u. The experimentally determined magnetic response of Mn(OH)Cl is paramagnetic in the range of 10-300 K. The estimated moment of 5.6 µB/f. u. indicates the high-spin d 5 configuration of manganese(II). We find hints for a long-range magnetic ordering below 10 K.
