All-solid-state lithium batteries (ASSLBs) with nonflammable solid electrolytes (SEs) deliver greatly enhanced safety characteristics. Furthermore, ASSLBs composed of cathodes with high working voltages, such as LiCoO 2 , LiNi x Co y Mn z O 2 (x + y + z = 1, NCM), LiNi x Co y Al z O 2 (x + y + z = 1, NCA), LiMn x Fe y PO 4 (x + y = 1, LMFP), and LiNi 0.5 Mn 1.5 O 4 (LNMO), and a lithium metal anode can achieve comparable or better performance compared with that of LLBs in terms of energy density. Therefore, high-voltage ASSLBs have been regarded as the most promising next-generation batteries. Although significant progress has been achieved in high-voltage ASSLBs research, their development still faces multiple challenges. To facilitate further effective and target-oriented research on highvoltage ASSLBs, a summary of recent research progress is urgently needed. In this review, recent research progress in high-voltage ASSLBs is summarized from the perspectives of SEs modification, interfacial challenges and their corresponding solutions for cathodes, and high-voltage composite cathode design for practical applications. Finally, the authors' perspectives on the state of current ASSLBs research, aiming to propose possible research directions for the future development of high-voltage ASSLBs.

A facile and eco-friendly one-pot approach was utilized to synthesize a rGO-wrapped FeS nanoflakes composite, delivering a reversible capacity of 325 mA h g−1 at a large rate of 5.0 A g−1 after 1000 cycles.

A unique Co3O4 material, with a peony-like architecture assembled with ultrathin porous nanosheets, could display unprecedented rate capabilities when acting as the anode for lithium-ion batteries.

Poly­(ethylene oxide) (PEO)-based composite solid electrolytes (CSEs) are considered as one of the most promising candidates for all-solid-state lithium batteries (ASSLBs). However, a key challenge for their further development is to solve the main issues of low ionic conductivity and poor mechanical strength, which can lead to insufficient capacity and stability. Herein, β-cyclodextrin (β-CD) is first demonstrated as a multifunctional filler that can form a continuous hydrogen bond network with the ether oxygen unit from the PEO matrix, thus improving the comprehensive performances of the PEO-based CSE. By relevant characterizations, it is demonstrated that β-CD is uniformly dispersed into the PEO substrate, inducing adequate dissociation of lithium salt and enhancing mechanical strength through hydrogen bond interactions. In a Li/Li symmetric battery, the β-CD-integrated PEO-based (PEO-LiTFSI-15% β-CD) CSE works well at a critical current density up to 1.0 mA cm–2 and retains stable lithium plating/stripping for more than 1000 h. Such reliable properties also enable its superior performance in LiFePO4-based ASSLBs, with specific capacities of 123.6 and 114.0 mA h g–1 as well as about 100 and 81.8% capacity retention over 300 and 700 cycles at 1 and 2 C (1 C = 170 mA g–1), respectively.

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Investigations into conversion-type materials such as transition-metal oxides have dominated in energy-storage systems, especially for lithium ion batteries in recent years. A common understanding of taking account of high energy density and high power density allows us to design reasonable electrodes. In this study, the unique Fe3O4@nitrogen-doped carbon (denoted as Fe3O4@NC) nanocapsule with self-formed channels was synthesized based on a facile hydrothermal-coating-annealing route. With respect to the effect of this rational architecture on lithium-storage performance, excellent behavior (a high reversible capacity of 480 mAh g–1) could be maintained at 20 A g–1 during 1000 cycles, with an average Coulombic efficiency of 99.97%. It also means that such a Fe3O4@NC electrode can meet a fast-charge challenge (end-of-charge within ∼2 min). By a series of investigations, we certainly considered that uniform carbon coating improved electrical conductivity and acted as a buffer layer to accommodate volume variations of Fe3O4 nanoparticles during cycling. It is more interesting that self-formed channels can effectively shorten the ion diffusion path and provide a necessary space to buffer volume expansion as well. Benefiting from these synergetic advantages, this Fe3O4@NC nanocapsule also delivered outstanding electrochemical performances in full cells.

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