Low voltage anode materials for lithium-ion batteries

Studies of anode materials due to the rapidly growing demand for lithium-ion batteries (LIBs) are an active area of research. However, the primary focus is on the specific capacity and cyclability. An essential requirement of electrode materials is the operating voltage, which is defined by the redox potential, but there is a tendency to sacrifice this feature in favor of higher capacities. For the cathode materials, there is a common categorization based on the operating voltage (e.g., high voltage cathode delivering a redox potential between 4.5-5.0 V vs. Li/Li+), but there is no such categorization for anode materials. The present manuscript aims to provide a general review of the anode material to highlight the importance of the operating voltage for an anode candidate. Furthermore, it is described that compositing the anode materials with carbon nanomaterials can increase the specific capacity for the delithiation, but part of this capacity is due to the carbon capacitance or pseudocapacitance mostly occurring at high potentials, which cannot be gained in the full cell performance. This class of pseudocapacitive anode materials can be of potential interest for energy storage but not appropriate candidates for the conventional LIBs. It is also emphasized that the delithiation process is the main duty of an anode material when a LIB is working.