The Potential Regulation of Working Anode for Long-Term Zero-Volt Storage at 37 °C in Li-Ion Batteries

The advanced lithium-ion batteries that can tolerate zero-volt storage (ZVS) are in high demand for implantable medical devices and spacecraft. However, ZVS can raise the anode potential, leading to Cu current collector dissolution and solid-electrolyte interphase (SEI) degradation, especially at 37 °C. In this contribution, by quantitatively regulating the dosage of Li6CoO4 cathode additives, controllable potential of the working anode under abusive-discharge conditions is demonstrated. The addition of Li6CoO4 keeps zero-crossing potential (ZCP) and the potential of ZVS below 2.0 V (vs Li/Li+) for LiCoO2|mesocarbon microbead cells at 37 °C. The capacity retention ratio (CRR) increases from 69.1% and 35.9% to 98.6% and 90.8% after 10 and 20 days of ZVS, respectively. The Cu dissolution and SEI degradation are effectively suppressed, while the over-lithiated cathode exhibits high reversible capacity after ZVS. The limiting conditions of long-term ZVS are further explored and a corresponding guide map is designed. When quantitatively regulating ZCP and the potential in ZVS, Cu dissolution, SEI degradation, and irreversible conversion of the cathode constitute the limiting conditions. This contribution designs the most reasonable potential range for ZVS protection at 37 °C, and realizes the best CRR record through precise potential regulation for the first time.

Degradation Mechanism Study and Safety Hazard Analysis of Overdischarge on Commercialized Lithium-ion Batteries

With the continuous improvement of the energy density of traction batteries for electric vehicles, the safety of batteries over their entire lifecycle has become the most critical issue in the development of electric vehicles. Abuse of electricity encountered in the application of batteries has a great impact on the safety of traction batteries. In this study, focused on the overdischarge phenomenon that is most likely to be encountered in the practical use of electric vehicles and grid storage, the impact of overdischarge on battery performance degradation is analyzed by neutron imaging technology and its safety hazards is systematically explored, combined with multimethods including electrochemical analysis and structural characterization. Results reveal the deterioration of the internal structure of traction batteries due to the overdischarge behavior and play a guiding role in the testing and evaluation of the safety of traction batteries.

Bipolar Electrodes for Next-Generation Rechargeable Batteries

The development of advanced rechargeable batteries provides a great opportunity for basic and applied researchers to collectively overcome challenging scientific and technological barriers that directly address a critical need for energy storage. In addition to novel battery chemistries often scientifically reviewed, advanced battery structures via technological innovations that boost battery performance are also worthy of attention. In this context, bipolar electrodes (BEs) are capable of improving the specific power, simplifying cell components, and reducing manufacturing costs for rechargeable batteries. By focusing on the fundamentals and applications of BEs in rechargeable batteries, the rational utilization of BEs from an academic perspective is considered. The progress and challenges of BEs are discussed and summarized in detail. Key techniques and materials for enabling BEs are highlighted and an outlook for the future directions of BEs that involve emerging concepts, such as wearable devices, all-solid-state batteries, fast spraying fabrication, and recyclable secondary batteries, is also presented.

Sustainability-inspired cell design for a fully recyclable sodium ion battery

Large-scale applications of rechargeable batteries consume nonrenewable resources and produce massive amounts of end-of-life wastes, which raise sustainability concerns in terms of manufacturing, environmental, and ecological costs. Therefore, the recyclability and sustainability of a battery should be considered at the design stage by using naturally abundant resources and recyclable battery technology. Herein, we design a fully recyclable rechargeable sodium ion battery with bipolar electrode structure using Na₃V₂(PO₄)₃ as an electrode material and aluminum foil as the shared current collector. Such a design allows exceptional sodium ion battery performance in terms of high-power correspondence and long-term stability and enables the recycling of ∼100% Na₃V₂(PO₄)₃ and ∼99.1% elemental aluminum without the release of toxic wastes, resulting in a solid-component recycling efficiency of >98.0%. The successful incorporation of sustainability into battery design suggests that closed-loop recycling and the reutilization of battery materials can be achieved in next-generation energy storage technologies.

A LiFePO4/Li2Sn hybrid system with enhanced Li-ion storage performance

A LiFePO₄/Li₂S_n hybrid system was designed using a LiFePO₄ cathode and a Li₂S_n-added electrolyte to improve the Li-ion storage performance.