Solid-state electrolytes (SSEs) are widely considered as an “enabler” to inhibit dendrite growth of lithium-metal anodes for high-energy and highly safe next-generation batteries. However, recent studies demonstrated that lithium dendrites form in working SSEs. Theoretically, dendrite inhibition can be achieved in perfect SSEs without any defects, while dendrite growth is extensively observed in practical SSEs with poor interface stability, large grain boundaries, voids, and partial electronic conductivity. In this Review, dendrite growth behaviors in SSEs, including polymer and inorganic electrolytes, are comprehensively summarized. The observed dendrite morphology in these SSEs, possible formation mechanisms, and some solutions are analyzed. Clear perspectives and some suggestions are also presented for the further development of SSEs in lithium-metal batteries. This Review intends to shed fresh light on the understanding of dendrite growth in SSEs and the rational design of the architecture and materials for SSEs matching the lithium-metal anode.

Fundamentals, challenges, and solutions towards fast-charging graphite anodes are summarized in this review, with insights into the future research and development to enable batteries suitable for fast-charging application.

Fast charging enables electronic devices to be charged in a very short time, which is essential for next‐generation energy storage systems. However, the increase of safety risks and low coulombic efficiency resulting from fast charging severely hamper the practical applications of this technology. This Review summarizes the challenges and recent progress of lithium batteries for fast charging. First, it describes the definition of fast charging and proposes a critical value of ionic and electrical conductivity of electrodes for fast charging in a working battery. Then based on this definition, the requirements and optimization strategies of the electrode, electrolyte, and electrode/electrolyte interface for fast charging are proposed. Finally, a general conclusion and perspectives on the better understanding of lithium batteries with fast charging capability are presented.

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In addition, LIBs still suffer from high cost, limited durability, and poor safety. [3] As a consequence, an alternative rechargeable battery system is crucial to cope with the growing demands of electric vehicles. [4] The prior demand for a power battery is security. The conventional power batteries suffered from frequent combustion accidents. The ascending voltage of cathodes will lead to stability concerns. Most of the thermal runaway is triggered by the reaction derived from electrodes. [6] The decomposition of cathode materials releases heat and oxygen and will trigger the combustion of flammable organic electrolytes. However, the high-energy cathode is essential for an energy-dense battery. Hence the substitution of conventional organic electrolytes is feasible to both enhance the energy density and battery safety. [5,7] The replacement of organic liquid electrolytes (OLEs) with solid-state electrolytes (SSEs) provides a promising future for the large-scale application of lithium metal batteries (LMBs). SSEs with wide electrochemical stability windows and high modulus possess the potential to enable high-capacity electrode materials and prevent Li dendritic deposition. [8] Besides, the SSEs also possess good thermal stability, which enables a wide operation temperature range and avoid the combustion risk. The introduction of SSEs allows a simplified battery design and minimization of inactive materials, consequently increasing energy density at the cell-level. Moreover, the solid-state electrolytes enable the employment of Li metal anodes, which is considered as the most promising anode for next-generation rechargeable batteries due to its ultrahigh theoretical specific capacity of 3860 mAh g −1 and lowest negative electrochemical potential (−3.04 V vs the standard hydrogen electrode). [9] In conventional organic electrolytes, lithium metal suffers from the unstable solid-state interphase, dendrite penetration, and pulverization issues. [1c,10] The rapid deterioration of LMBs is attributed to the high reactivity of lithium metal. [11] Virtually most conventional OLEs can be reduced at the Li surface, forming unstable solid electrolyte interphase (SEI). During repeated charge-discharge cycles, Li tends to generate dendritic morphology because of nonuniform current/ion distribution. [12] Lithium dendrites normally lead to the fracture and regeneration of SEI, further aggravating the dendrite growth. [12a,13] The The scale-up process of solid-state lithium metal batteries is of great importance in the context of improving the safety and energy density of battery systems. Replacing the conventional organic liquid electrolytes (OLEs) with solid-state electrolytes (SSEs) opens a new path for addressing increasing energy demands. Advanced approaches have been validated in lab-scale cells, but only a few successful results can be applied on the practical scale. Herein, the battery systems enabled by SSEs are briefly reviewed and the difficulties and challenges for both lab-level cells and large-scale batteries from...

As anodes of Li-ion batteries, copper oxides (CuO) have a high theoretical specific capacity (674 mA h g ) but own poor cyclic stability owing to the large volume expansion and low conductivity in charges/discharges. Incorporating reduced graphene oxide (rGO) into CuO anodes with conventional methods fails to build robust interaction between rGO and CuO to efficiently improve the overall anode performance. Here, Cu O/CuO/reduced graphene oxides (Cu O/CuO/rGO) with a 3D hierarchical nanostructure are synthesized with a facile, single-step hydrothermal method. The Cu O/CuO/rGO anode exhibits remarkable cyclic and high-rate performances, and particularly the anode with 25 wt% rGO owns the best performance among all samples, delivering a record capacity of 550 mA h g at 0.5 C after 100 cycles. The pronounced performances are attributed to the highly efficient charge transfer in CuO nanosheets encapsulated in rGO network and the mitigated volume expansion of the anode owing to its robust 3D hierarchical nanostructure.

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Structural/compositional characteristics at the anode/electrolyte interface are of paramount importance for the practical performance of lithium ion batteries, including cyclic stability, rate capacity, and operational safety. The anode‐electrolyte interface with traditional separator technology is featured with inevitable phase discontinuity and fails to support the stable operation of lithium ion batteries based on large‐capacity anodes with structural change in charges/discharges, such as transition metal oxide anodes. In this work, an anode/electrolyte framework based on an oxide anode and an active‐oxide‐incorporated separator is proposed for the first time and investigated for lithium ion batteries. The architecture builds a robust anode‐separator interface in LIBs, shortens Li+ diffusion path, accelerates electron transport, and mitigates the volume change of the oxide anode in electrochemical reactions. Remarkably, 4 wt% CuO addition in the separator leads to a 17% enhancement in the overall capacity of a battery with a CuO anode. The battery delivers an unparalleled record reversible capacity of 637.2 mAh g−1 with a 99% capacity retention after 100 charge/discharge cycles at 0.5 C. The high performance are attributed to the robust anode‐separator interface, which gives rise to enhanced interaction between the oxide anode and the same‐oxide‐incorporated composite in the separator.