The booming electric vehicle industry continues to place higher requirements on power batteries related to economic-cost, power density and safety. The positive electrode materials play an important role in the energy storage performance of the battery. The nickel-rich NCM (LiNi_xCo_yMn_zO₂ with x + y + z = 1) materials have received increasing attention due to their high energy density, which can satisfy the demand of commercial-grade power batteries. Prominently, single-crystal nickel-rich electrodes with s unique micron-scale single-crystal structure possess excellent electrochemical and mechanical performance, even when tested at high rates, high cut-off voltages and high temperatures. In this review, we outline in brief the characteristics, problems faced and countermeasures of nickel-rich NCM materials. Then the distinguishing features and main synthesis methods of single-crystal nickel-rich NCM materials are summarized. Some existing issues and modification methods are also discussed in detail, especially the optimization strategies under harsh conditions. Finally, an outlook on the future development of single-crystal nickel-rich materials is provided. This work is expected to provide some reference for research on single-crystal nickel-rich ternary materials with high energy density, high safety levels, long-life, and their contribution to sustainable development.

A friction loss model for a loading brake tester with adjusted shaft distance was constructed to correct the test results of the braking rate of the loading shaft, which could largely improve the accuracy of automobile braking performance tests. Specifically, the influence of tire pressure, vehicle axle load, placement angle, and vehicle speed on the friction loss was tested and analyzed on the tester. The friction loss model for the tester was constructed based on the first defined relative slip and placement angle, which was validated through actual tests on four types of vehicles. The results showed that the maximum relative error between the simulation and the measured values is 2.2%, indicating the friction loss model is valid and can provide a basis for correcting the braking force of automobile brakes. Meanwhile, the maximum braking force increased from 3982 N to 4772 N, increased by 19.8%, when the placement angle was raised from 36.9° to 47.0°, demonstrating the effectiveness of constructing a friction loss model and enhancing the accuracy of the loading brake tester with adjusted shaft distance test results. Accordingly, in order to improve the detection accuracy of the self-developed tester, the friction loss model is essential for correcting the friction loss caused by the change in the placement angle, and then the braking rate of the vehicle should be determined according to the relevant regulations stipulated in China, EU, USA, Japan, and other countries or regions, which can accurately reflect the performance of the vehicle’s braking system.

A friction loss model for brake testing platform is constructed to revise the braking force test results, which can largely improve the accuracy of automotive brake performance testing. Specifically, the influence of tire pressure, vehicle axle load, placement angle and vehicle speed on the friction loss is tested and analyzed on a wheelbase adjustable automotive anti-force brake testing platform. The friction loss model for the platform is constructed based on the defined relative slip and placement angle, which is validated through actual tests on four types of vehicles. The results showed that the maximum relative error between the values of the model calculated simulation and the measured was 2.2%, indicating the friction loss model is valid and can provide a basis for revising the braking force of automotive brake. Meanwhile, the maximum braking force increases from 3982 N to 4772 N, increased by 19.8%, when the placement angle increased from 36.9° to 47.0°. Accordingly, in order to improve the accuracy of detection results of the automotive anti-force rolling brake testing platform, the friction loss caused by the change in the placement angle should be revised, and then braking rate of the vehicle should be judged according to GB 7258-2017 and GB 38900-2020.