In developing electrode materials for next-generation Li-ion batteries, significant efforts have been given to the energy, power density and cycling stability, with much less (if any) attention paid to the energy efficiency – arguably, the most important practical measure for large-scale applications. This is particularly true for the oxygen-redox active electrodes, such as Li_1.2Ni_0.13Co_0.13Mn_0.54O₂, the notorious energy-inefficient cathode that has an extremely high capacity but comes with large voltage hysteresis and voltage decay. Herein, we report the rational design of an energy-efficient Li-rich layered cathode along with high energy, power density and cycling stability enabled by tuning oxygen redox activity. Specifically, the target material Li_1.12Ni_0.22Co_0.13Mn_0.52O₂ exhibits an ultrahigh energy efficiency at 1 C (90.6%), high capacity (> 200 mAh g⁻¹) with 98.9% retention and less than 150 mV decay at the extended 200 cycles. Through direct comparison between the material and Li_1.2Ni_0.13Co_0.13Mn_0.54O₂, we show that the compositional change, although slightly, greatly improves the oxygen redox kinetics and reversibility, thereby boosts energy efficiency. The findings offer a strategy to narrow the gap between scientific interest and practical application of oxygen-redox chemistry.

在开发用于下一代锂离子电池的电极材料时，已经在能量，功率密度和循环稳定性方面做出了巨大努力，而对能效的关注却很少（如果有的话）–可以说，这是最重要的实用措施。大规模应用。对于氧-氧化还原活性电极尤其如此，例如Li _1.2 Ni _0.13 Co _0.13 Mn _0.54 O ₂，臭名昭著的低能效阴极，具有极高的容量，但具有较大的电压滞后和电压衰减。在这里，我们报告了合理设计的节能型富锂层状阴极，以及通过调节氧气氧化还原活性而实现的高能量，功率密度和循环稳定性。具体而言，目标材料Li _1.12 Ni _0.22 Co _0.13 Mn _0.52 O ₂在1 C（90.6％）时表现出超高的能量效率，高容量（> 200 mAh g ^-1），保留率达98.9％，并且在放电时的衰减小于150 mV。延长了200个周期。通过直接比较材料与Li _1.2 Ni _0.13 Co _0.13Mn _0.54 O ₂，我们表明，成分的变化虽然略有改变，但可以极大地改善氧气的氧化还原动力学和可逆性，从而提高能源效率。这些发现提供了一种缩小科学兴趣与氧-氧化还原化学的实际应用之间的差距的策略。