With the low redox potential of −3.04 V (vs SHE) and ultrahigh theoretical capacity of 3862 mAh g −1 , lithium metal has been considered as promising anode material. However, lithium metal battery has ever suffered a trough in the past few decades due to its safety issues. Over the years, the limited energy density of the lithium-ion battery cannot meet the growing demands of the advanced energy storage devices. Therefore, lithium metal anodes receive renewed attention, which have the potential to achieve high-energy batteries. In this review, the history of the lithium anode is reviewed first. Then the failure mechanism of the lithium anode is analyzed, including dendrite, dead lithium, corrosion, and volume expansion of the lithium anode. Further, the strategies to alleviate the lithium anode issues in recent years are discussed emphatically. Eventually, remaining challenges of these strategies and possible research directions of lithium-anode modification are presented to inspire innovation of lithium anode.

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Transition metal oxides (TMOs) are considered as the prospective anode materials in lithium‐ion batteries (LIBs). Nevertheless, the disadvantages, including large volume variation and poor electrical conductivity, obstruct these materials to meet the needs of practical application. Well‐designed mesoporous nanostructures and electronic structure modulation can enhance the electron/Li‐ions diffusion kinetics. Herein, a unique mesoporous molybdenum dioxide/molybdenum phosphide heterostructure nanobelts (meso‐MoO2/MoP‐NBs) composed of uniform nanoparticles is obtained by one‐step phosphorization process. The Mott–Schottky tests and density functional theory calculations demonstrated that meso‐MoO2/MoP‐NBs possesses superior electronic conductivity. The detailed lithium storage mechanism (solid solution reaction for MoP and partial conversion for MoO2), small change ratio of crystal structure and fast electronic/ionic diffusion behavior of meso‐MoO2/MoP‐NBs are systematically investigated by operando X‐ray diffraction, ex situ transmission electron microscopy, and kinetic analysis. Benefiting from the synergistic effects, the meso‐MoO2/MoP‐NBs displays a remarkable cycling performance (515 mAh g−1 after 1000 cycles at 1 A g−1) and excellent rate capability (291 mAh g−1 at 8 A g−1). These findings can shed light on the behavior of the electron/ion regulation in heterostructures and provide a potential route to develop high‐performance lithium‐ion storage materials.

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Sodium‐based energy storage technologies are potential candidates for large‐scale grid applications owing to the earth abundance and low cost of sodium resources. Transition metal phosphides, e.g. MoP, are promising anode materials for sodium‐ion storage, while their detailed reaction mechanisms remain largely unexplored. Herein, the sodium‐ion storage mechanism of hexagonal MoP is systematically investigated through experimental characterizations, density functional theory calculations, and kinetics analysis. Briefly, it is found that the naturally covered surface amorphous molybdenum oxides layers on the MoP grains undergo a faradaic redox reaction during sodiation and desodiation, while the inner crystalline MoP remains unchanged. Remarkably, the MoP anode exhibits a pseudocapacitive‐dominated behavior, enabling the high‐rate sodium storage performance. By coupling the pseudocapacitive anode with a high‐rate‐battery‐type Na3V2O2(PO4)2F@rGO cathode, a novel sodium‐ion full cell delivers a high energy density of 157 Wh kg−1 at 97 W kg−1 and even 52 Wh kg−1 at 9316 W kg−1. These findings present the deep understanding of the sodium‐ion storage mechanism in hexagonal MoP and offer a potential route for the design of high‐rate sodium‐ion storage materials and devices.