Liquid-Phase Exfoliated Few-Layer Iodine Nanosheets for High-Rate Lithium-Iodine Batteries

Striking Differences in Regulating Effects on Electronic Transport of 2D Iodine-Based Devices from Metal and Nonmetal Dopants

Two-dimensional iodine-based materials, characterized by unique structures and properties, hold immense potential in electronics. Here, research indicates that doping metal/nonmetal dopants with small atomic numbers can substantially improve the equilibrium electronic transport of the new-type 2D iodine-based device. Unlike metal dopants, such enhancement from nonmetallic dopants varies greatly among elements, including sites. N doping remarkably exhibits the best enhancement. Essentially, small site doping, especially nonmetallic dopants, shows strong orbital hybridization with effective overlap, resulting in optimized distribution of electronic states and electrostatic potential and the formation of more efficient conduction channels, further enhancing the density of states (DOS) and electron transmission. In nonequilibrium, all dopants generally enhance conductance under lower biases but weaken conductance under higher biases. Such enhancement is much more pronounced in nonmetallic-doped devices in small sites, and in metallic elements, it is only achieved in Al. These devices all show increased currents with bias. The current of the undoped device can be weakened by doping metallic elements at higher voltages. At any voltage, N-small doping always maintains the optimal enhancement on current, and Mg doping almost retains the best weakening effect. Findings provide valuable theoretical guidance for such a 2D iodine material in high-performance tunable electronic devices and sensors.

Tunable Electronic Transport of New-Type 2D Iodine Materials Affected by the Doping of Metal Elements

2D iodine structures under high pressures are more attractive and valuable due to their special structures and excellent properties. Here, electronic transport properties of such 2D iodine structures are theoretically studied by considering the influence of the metal-element doping. In equilibrium, metal elements in Group 1 can enhance the conductance dramatically and show a better enhancement effect. Around the Fermi level, the transmission probability exceeds 1 and can be improved by the metal-element doping for all devices. In particular, the device density of states explains well the distinctions between transmission coefficients originating from different doping methods. Contrary to the "big" site doping, the "small" site doping changes transmission eigenstates greatly, with pronounced electronic states around doped atoms. In non-equilibrium, the conductance of all devices is almost weaker than the equilibrium conductance, decreasing at low voltages and fluctuating at high voltages with various amplitudes. Under biases, K-big doping shows the optimal enhancement effect, and Mg-small doping exhibits the most effective attenuation effect on conductance. Contrastingly, the currents of all devices increase with bias linearly. The metal-element doping can boost current at low biases and weaken current at high voltages. These findings contribute much to understanding the effects of defects on electronic properties and provide solid support for the application of new-type 2D iodine materials in controllable electronics and sensors.

Life cycle thinking and safe-and-sustainable-by-design approaches for the battery innovation landscape

Developments in battery technology are essential for the energy transition and need to follow the framework for safe-and-sustainable-by-design (SSbD) materials, chemicals, products, and processes as set by the EU. SSbD is a broad approach that ensures that chemicals/advanced materials/products/services are produced and used in a way to avoid harm to humans and the environment. Technical and policy-related literature was surveyed for battery technologies and recommendations were provided for a broad SSbD approach that remains firmly grounded in Life Cycle Thinking principles. The approach integrates functional performance and sustainability (safety, social, environmental, and economic) aspects throughout the life cycle of materials, products, and processes, and evaluates how their interactions reflect on SSbD parameters. 22 different types of batteries were analyzed in a life cycle thinking approach for criticality, toxicity/safety, environmental and social impact, circularity, functionality, and cost to ensure battery innovation has a green and sustainable purpose to avoid unintended consequences.