ABSTRACT
The practical application of lithium metal batteries is hindered by the poor reversibility and large volume change caused by the uncontrollable dendritic growth and the highly reactive surface. In this work, favorable Li deposition is achieved by generating gradient lithiophilicity and conductivity in an Ag-decorated graphene/holey graphene film (G-HGA). Dendrite-free Li metal is deposited on the G-HGA matrix, which greatly reduces the surface area and suppresses the side reaction between the electrolyte and the dendritic Li. The average Li-metal plating-stripping coulombic efficiency (CE) on the G-HGA matrix maintains â¼98.7% over 350 cycles, compared to a worse average CE (â¼97.3%) with the bare Cu matrix, only for less than 100 cycles. A full cell constructed by using LiFePO4 and prelithiated G-HGA exhibits excellent rate capability and a high capacity retention of 99.6% for 175 cycles at a low negative to positive capacity ratio of 1.13. This advanced design can inspire further development of high-energy and long-lived Li-metal batteries.
ABSTRACT
The brain-computer interface (BCI) has emerged in recent years and has attracted great attention. As an indispensable part of the BCI signal acquisition system, brain electrodes have a great influence on the quality of the signal, which determines the final effect. Due to the special usage scenario of brain electrodes, some specific properties are required for them. In this study, we review the development of three major types of EEG electrodes from the perspective of material selection and structural design, including dry electrodes, wet electrodes, and semi-dry electrodes. Additionally, we provide a reference for the current chaotic performance evaluation of EEG electrodes in some aspects such as electrochemical performance, stability, and so on. Moreover, the challenges and future expectations for EEG electrodes are analyzed.
