This chapter introduces AdaptPoW, a novel proof-of-work blockchain protocol that dynamically adjusts throughput based on transaction demands while eliminating duplicate transactions in concurrent blocks. The blockchain structure can expand or shrink exponentially, with mining difficulty automatically adjusting to maintain security. When transaction demands are high, the blockchain expands by allowing more concurrent blocks; when demands are low, it shrinks to reduce resource consumption. A mining power load balancing mechanism prevents adversaries from concentrating attacks on specific subchains, while a transaction de-duplication mechanism leverages transaction hash values to eliminate redundancy across concurrent blocks. Security analysis proves the protocol’s safety and liveness properties, demonstrating resilience against both double-spending and liveness attacks. Experimental results on Amazon EC2 with 1000 nodes show that AdaptPoW achieves adaptive throughput scaling up to 2810 transactions per second while maintaining consistent confirmation latency, significantly improving resource utilization compared to traditional blockchain systems.